Clinical studies of three oral prodrugs of 5-fluorouracil (capecitabine, UFT, S-1): a review

Hyaluronic acid-coated capecitabine nanostructures for CD44 receptor-mediated targeting in breast cancer therapy

Hyaluronic acid-coated capecitabine-loaded nanomicelles (HA-CAP-M) are synthesized to overcome the challenges associated with capecitabine (CAP) conventional delivery such as low permeability and systemic toxicity. Nanomicelles containing saponin, glycerol, and vitamin-E TPGS formulation of capecitabine were further encapsulated with hyaluronic acid (HA) for CD44 receptor-mediated targeting. Optimization of the formulation was carried out using a Box-Behnken design resulting in 17.8 nm particle size, 89.3% entrapment efficiency and a biphasic drug release profile. Characterization studies validated stability, spherical structure, and desirable encapsulation characteristics of the nanomicelles. Lowered critical micelle concentration (CMC) and acceptable drug release kinetics revealed improved thermodynamic stability and controlled drug release, as predicted by the Hixson-Crowell model. HA-CAP-M showed much higher permeability and cytotoxicity than the free CAP, with an IC50 of 2.964 μg mL-1 in in vitro experiments. AO/PI staining also demonstrated dose-dependent apoptosis in MCF-7 breast cancer cells and validated the highly effective active targeting of HA. In addition, the formulation demonstrated good stability during storage and dilution conditions, confirming its stability as a drug delivery platform. In conclusion, HA-functionalized nanomicelles provide a biocompatible and efficient system for the targeted breast cancer therapy, enhancing the therapeutic efficacy of capecitabine.

Effect of honey-ginger mouthwash on oral mucositis in patients undergoing chemotherapy

BACKGROUND

Oral mucositis is considered as one of the most prevalent complications of chemotherapy or radiation therapy in cancerous tumors, which can interrupt the patient's treatment and nutrition. This study therefore aimed to evaluate the efficacy of ginger-honey mouthwash on the prevention of chemotherapy-induced oral mucositis in patients suffering from various cancers.

MATERIALS AND METHODS

In this randomized clinical trial study, 70 patients receiving chemotherapy were divided into case and control groups. The former group (n = 34) received natural honey-ginger mouthwash and the latter (n = 36) used normal saline for 14 days. The presence and severity of oral mucositis, pain intensity, and other related characteristics were evaluated based on a two-part questionnaire (demographic and clinical information) and a checklist prepared from the protocols of the World Health Organization in each group.

RESULTS

During a 14-day intervention, patients received a 7-day intervention with ginger-honey mouthwash revealed a significant reduction in the mean severity of oral mucositis compared to the control group (p = 0.03). However, a 14-day intervention with ginger-honey mouthwash indicated no significant impact on the mean severity of oral mucositis (p = 0.6). In addition, no significant difference was observed in pain intensity between case and control groups during these 14 days.

CONCLUSIONS

This study suggests that a seven-day intervention with ginger-honey mouthwash has a beneficial effect on reducing the severity of mucositis in patients under chemotherapy, unlike a 14-day intervention. The honey-ginger mouthwash fails to have a significant effect on the pain intensity due to mucositis in patients undergoing chemotherapy.

Beyond chemotherapy: Exploring 5-FU resistance and stemness in colorectal cancer

Colorectal cancer (CRC) remains a significant global health challenge, demanding continuous advancements in treatment strategies. This review explores the complexities of targeting colorectal cancer stem cells (CSCs) and the mechanisms contributing to resistance to 5-fluorouracil (5-FU). The efficacy of 5-FU is enhanced by combination therapies such as FOLFOXIRI and targeted treatments like bevacizumab, cetuximab, and panitumumab, particularly in KRAS wild-type tumors, despite associated toxicity. Biomarkers like thymidylate synthase (TYMS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) are crucial for predicting 5-FU efficacy and resistance. Targeting CRC-CSCs remains challenging due to their inherent resistance to conventional therapies, marker variability, and the protective influence of the tumor microenvironment which promotes stemness and survival. Personalized treatment strategies are increasingly essential to address CRC's genetic and phenotypic diversity. Advances in immunotherapy, including immune checkpoint inhibitors and cancer vaccines, along with nanomedicine-based therapies, offer promising targeted drug delivery systems that enhance specificity, reduce toxicity, and provide novel approaches for overcoming resistance mechanisms. Integrating these innovative strategies with traditional therapies may enhance the effectiveness of CRC therapy by addressing the underlying causes of 5-FU resistance in CSCs.

Cardiotoxicity Associated With a Low Doses of 5-FU Promotes Morphoquantitative Changes in the Intrinsic Cardiac Nervous System

5-Fluorouracil (5-FU) is a chemotherapeutic that is used to treat solid tumors. However, 5-FU is associated with several side effects, including cardiotoxicity. Considering the importance of the intrinsic cardiac nervous system (ICNS) for the heart and that little is known about effects of 5-FU on this nervous system plexus, the purpose of the present study was to evaluate effects 5-FU at a low dose on the ICNS and oxidative and inflammatory effects in the heart in Wistar rats. The rats were divided into two groups: treated and 5-FU (n = 6/group). The control group received saline only. The treated group received the following clinical doses of 5-FU: 15 mg/kg for 4 consecutive days, followed by 6 mg/kg for 4 days alternated with non-treatment days, and finally 15 mg/kg as the last dose on day 14. On day 15, the rats were euthanized and underwent thoracotomy. The atria were used for histological analysis, and the ventricles were used for biochemical analysis. The results showed an increase in neuronal density and a decrease in ganglionic and neuronal area in the ICNS. Furthermore, tissue inflammation was observed, indicated by an increase in proinflammatory factors and the enzymatic activity of myeloperoxidase and n-acetyl-glucosaminidase. Oxidative stress was also observed, confirmed by a reduction of endogenous antioxidant defenses and the presence of lipoperoxidation. Treatment with 5-FU also caused cardiac atrophy and fibrosis. These findings indicate that cardiotoxicity is present with 5-FU treatment and affects the morphometric aspects of the ICNS.

Esterase-Responsive Self-Immolative Prodrugs for the Sustained Delivery of the Anticancer Drug 5-Fluorouracil with Turn-On Fluorescence

Stimuli-responsive prodrugs of anticancer drugs are advantageous for the selective delivery of drugs to cancer cells with minimized off-target side effects. In the present study, esterase-activatable fluorogenic prodrugs of the chemotherapeutic drug 5-fluorouracil (5-FU) have been rationally designed and synthesized using multi-step organic synthesis. While 5-FU was connected directly with the fluorophore via a C-N bond in the prodrug BJ-50, an additional self-immolative benzylic spacer with a carbonate linker was incorporated in the prodrug BJ-92. Although absorption and emission spectroscopic studies revealed the activation of both the prodrugs by porcine liver esterase (PLE), reverse-phase HPLC studies confirmed the inability of BJ-50 to release the active drug 5-FU. In contrast, a sustained release of 5-FU and Cou-OH was observed from BJ-92 in the presence of PLE. The endogenous esterase-mediated activation of the prodrug BJ-92 was validated by the turn-on fluorescence in A549 cells and the anti-proliferative activities in A549, and HEK-293 cells. Modulation of the expression of a few cancer marker proteins by BJ-92 and 5-FU was studied to evaluate their anticancer activities. As esterases are overexpressed in cancer cells, the prodrug in the present study would be helpful in selectively delivering 5-FU to cancer cells with reduced off-target side-effects.

Irinotecan-Induced Site-Specific Pigmentation in the Plantar Region of Mice

Skin pigmentation is a widely recognized side effect of cancer chemotherapy that can negatively affect patient QOL. However, although numerous case reports have documented pigmentation caused by anticancer drugs, the precise mechanisms remain unclear. Among such pigmentation, that induced by 5-fluorouracil (5-FU) has garnered considerable attention, whereas reports on irinotecan-induced pigmentation are comparatively limited. In this study, we investigated the pigmentation-related effects of irinotecan in colored hairless mice. Mice received intraperitoneal injections of 20 mg/kg irinotecan, and we subsequently examined the pigmentation of the plantar and buttock regions. The results indicated that irinotecan specifically induces pigmentation in the plantar region, with no pigmentation observed on the buttocks. In contrast, pigmentation was noted on the buttocks, although not in the plantar region, in the control mice treated with 5-FU and cytarabine. Furthermore, irinotecan treatment promoted a marked elevation in the expression of tyrosinase, cAMP response element binding protein (CREB), and microphthalmia-associated transcription factor (MITF) in the plantar region, whereas no significant changes were observed in the buttocks. These findings indicate that irinotecan leads to site-specific pigmentation in the sole of the foot, thereby highlighting the potential for anticancer drugs to cause localized pigmentation.

The Prevalence of 5-Fluorouracil and Capecitabine Cardiotoxicity: A Systematic Review and Meta-Analysis

Background

The incidence of cardiotoxicity events in patients who use 5-fluorouracil (5-FU) and capecitabine monotherapy remains unclear since previous studies reported the prevalence in patients who used combination regimens. We aimed to systematically review and meta-analyze the incidence of cardiotoxicity in fluorouracil and capecitabine monotherapy users.

Methods

The study protocol was registered with PROSPERO (CRD42023441627). Systematic searches were conducted in five databases (CINAHL, OpenGrey, PubMed, ScienceDirect, and Scopus). The Cochrane Risk-of-Bias tool and the Risk Of Bias In Non-randomized Studies were used to evaluate the risk of bias. Pooled prevalence and 95% confidence interval (CI) were calculated using the DerSimonian-Laird random effect models. The funnel plot was used to assess the publication bias.

Results

Eighty studies were included. There were 24 randomized controlled trials (RCTs) with low to high risk of bias and 56 non-RCTs with critical risk of bias. The pooled prevalence of cardiotoxicity from 5-FU was 3.5% (95% CI: 2.7 - 4.2; P < 0.001; I2 = 73.86%). The pooled prevalence of cardiotoxicity in capecitabine users was 2.8% (95% CI: 1.6 - 4.0; P < 0.001; I2 = 72.62%).

Conclusions

The prevalence of cardiotoxicity from 5-FU and capecitabine was classified as common. Cardiotoxicity may have not been associated with the cumulative dose of 5-FU or capecitabine.

Association Between Changes in Plasma Capecitabine Concentrations and Adverse Events in the Treatment of Colorectal Cancer

Background Therapeutic drug monitoring (TDM) is an effective approach to improving the efficacy of drugs with a narrow therapeutic index and high toxicity. TDM-guided dosing of 5-fluorouracil (5-FU) has been shown to result in superior efficacy and fewer adverse events compared to body surface area (BSA)-based dosing. Therefore, accurate measurement of plasma 5-FU concentrations after capecitabine administration is necessary. Capecitabine is a prodrug of 5-FU and is metabolized to 5-FU in multiple steps in the gastrointestinal tract, liver, and within tumors. To solve the problem of frequent blood draws for TDM, we reduced the number of blood draws to two and examined whether changes in 5-FU concentration correlated with adverse events. Methods This study investigated the relationship between the changes in plasma 5-FU concentrations after one and two hours of capecitabine administration in 36 patients and adverse events based on drug concentrations determined after adding 5-NU to the plasma samples. Concentration gradients and adverse events were estimated using the Mann-Whitney test. Results The median one- and two-hour plasma 5-FU concentrations were 67.5 (range 5-307) and 85.5 (range 19-246) ng/mL, respectively. The plasma 5-FU concentration gradient, defined as the difference between the one- and two-hour concentrations, was significantly higher in patients with diarrhea and nausea (p = 0.0234 and p = 0.0409, respectively). Conclusion The high plasma 5-FU concentration gradient suggests rapid degradation of 5-FU into its metabolites, which may lead to predict intestinal mucosal damage, diarrhea, and nausea.

PAQR4 oncogene: a novel target for cancer therapy

Despite decades of basic and clinical research and trials of promising new therapies, cancer remains a major cause of morbidity and mortality due to the emergence of drug resistance to anticancer drugs. These resistance events have a very well-understood underlying mechanism, and their therapeutic relevance has long been recognized. Thus, drug resistance continues to be a major obstacle to providing cancer patients with the intended "cure". PAQR4 (Progestin and AdipoQ Receptor Family Member 4) gene is a recently identified novel protein-coding gene associated with various human cancers and acts through different signaling pathways. PAQR4 has a significant influence on multiple proteins that may regulate various gene expressions and may develop chemoresistance. This review discusses the roles of PAQR4 in tumor immunity, carcinogenesis, and chemoresistance. This paper is the first review, discussing PAQR4 in the pathogenesis of cancer. The review further explores the PAQR4 as a potential target in various malignancies.

Molecular panorama of therapy resistance in prostate cancer: a pre-clinical and bioinformatics analysis for clinical translation

Prostate cancer (PCa) is a malignant disorder of prostate gland being asymptomatic in early stages and high metastatic potential in advanced stages. The chemotherapy and surgical resection have provided favourable prognosis of PCa patients, but advanced and aggressive forms of PCa including CRPC and AVPC lack response to therapy properly, and therefore, prognosis of patients is deteriorated. At the advanced stages, PCa cells do not respond to chemotherapy and radiotherapy in a satisfactory level, and therefore, therapy resistance is emerged. Molecular profile analysis of PCa cells reveals the apoptosis suppression, pro-survival autophagy induction, and EMT induction as factors in escalating malignant of cancer cells and development of therapy resistance. The dysregulation in molecular profile of PCa including upregulation of STAT3 and PI3K/Akt, downregulation of STAT3, and aberrant expression of non-coding RNAs are determining factor for response of cancer cells to chemotherapy. Because of prevalence of drug resistance in PCa, combination therapy including co-utilization of anti-cancer drugs and nanotherapeutic approaches has been suggested in PCa therapy. As a result of increase in DNA damage repair, PCa cells induce radioresistance and RelB overexpression prevents irradiation-mediated cell death. Similar to chemotherapy, nanomaterials are promising for promoting radiosensitivity through delivery of cargo, improving accumulation in PCa cells, and targeting survival-related pathways. In respect to emergence of immunotherapy as a new tool in PCa suppression, tumour cells are able to increase PD-L1 expression and inactivate NK cells in mediating immune evasion. The bioinformatics analysis for evaluation of drug resistance-related genes has been performed.

Oxaliplatin(IV) Prodrugs Functionalized with Gemcitabine and Capecitabine Induce Blockage of Colorectal Cancer Cell Growth-An Investigation of the Activation Mechanism and Their Nanoformulation

The use of platinum-based anticancer drugs, such as cisplatin, oxaliplatin, and carboplatin, is a common frontline option in cancer management, but they have debilitating side effects and can lead to drug resistance. Combination therapy with other chemotherapeutic agents, such as capecitabine and gemcitabine, has been explored. One approach to overcome these limitations is the modification of traditional Pt(II) drugs to obtain new molecules with an improved pharmacological profile, such as Pt(IV) prodrugs. The design, synthesis, and characterization of two novel Pt(IV) prodrugs based on oxaliplatin bearing the anticancer drugs gemcitabine or capecitabine in the axial positions have been reported. These complexes were able to dissociate into their constituents to promote cell death and induce apoptosis and cell cycle blockade in a representative colorectal cancer cell model. Specifically, the complex bearing gemcitabine resulted in being the most active on the HCT116 colorectal cancer cell line with an IC50 value of 0.49 ± 0.04. A pilot study on the encapsulation of these complexes in biocompatible PLGA-PEG nanoparticles is also included to confirm the retention of the pharmacological properties and cellular drug uptake, opening up to the possible delivery of the studied complexes through their nanoformulation.

Multifunctional chitosan-bimetallic nanocarrier deliver 5-fluorouracil for enhanced treatment of pancreatic and triple-negative breast cancer

This work aimed to prepare multifunctional aptamer-conjugated, photothermally responsive 5-fluorouracil (5fu)-loaded chitosan-bimetallic (Au/Pd) nanoparticles (APT-CS-5fu-Au/Pd NPs) for improved cytotoxicity in two cancer cell lines (PANC-1 and MDA-MD 231). The CS-5fu-Au/Pd NPs were polydispersed with a size of 34.43 ± 1.59 nm. FTIR analysis indicated the presence of CS, 5fu in CS-5fu-Au/Pd NPs. The 2 theta degrees in CS-5fu-Au/Pd NPs accounted for CS and Au/Pd. Additionally, AGE revealed the conjugation of APT in CS-5fu-Au/Pd NPs. The APT-CS-5fu-Au/Pd NPs (180 μg/mL) with NIR treatment increased the temperature to >50 °C. The optimized 5fu input was 0.075 % in CS-5fu-Au/Pd NPs, exhibiting a hydrodynamic size of 112.96 ± 17.23 nm, DEE of 64.2 ± 3.77 %, and DLE of 11.1 ± 0.65 %. A higher level of 5fu release (69.8 ± 2.78 %) was observed under pH 5.4 at 74 h. In conclusion, NIR-APT-CS-5fu-Au/Pd NPs did not cause toxicity to RBC and Egg CAM, but increased cytotoxicity in MDA-MB 231 and PANC-1 cells by triggering oxidative stress-mediated cell death.

Bovine Serum Albumin as a Platform for Designing Biologically Active Nanocarriers-Experimental and Computational Studies

Due to the specificity of their structure, protein systems are adapted to carry various ligands. The structure of many proteins potentially allows for two types of immobilization of a therapeutic agent, either on the outer surface of the protein or within the protein structure. The existence of two active sites in BSA's structure, the so-called Sudlow I and II, was confirmed. The conducted research involved determining the effectiveness of BSA as a potential carrier of 5-fluorouracil (5FU). 5-fluorouracil is a broad-spectrum anticancer drug targeting solid tumors. The research was carried out to estimate the physicochemical properties of the system using complementary measurement techniques. The optimization of the complex formation conditions made it possible to obtain significant correlations between the form of the drug and the effective localization of the active substance in the structure of the protein molecule. The presence of two amino groups in the 5FU structure contributes to the deprotonation of the molecule at high pH values (pH > 8) and the transition to the anionic form (AN1 and AN3). To investigate the binding affinity of the tautomeric form with BSA, UV-vis absorption, fluorescence quenching, zeta potential, QCM-D, and CD spectroscopic studies were performed. The experimental research was supported by molecular dynamics (MD) simulations and molecular docking. The simulations confirm the potential location of 5FU tautomers inside the BSA structure and on its surface.

Development of 5-fluorouracil-dichloroacetate mutual prodrugs as anticancer agents

5-Fluorouracil (5-FU) is one of the most widely applied chemotherapeutic agents with a broad spectrum of activity. However, despite this versatile activity, its use poses many limitations. Herein, novel derivatives of 5-FU and dichloroacetic acid have been designed and synthesized as a new type of codrugs, also known as mutual prodrugs, to overcome the drawbacks of 5-FU and enhance its therapeutic efficiency. The stability of the obtained compounds has been tested at various pH values using different analytical techniques, namely HPLC and potentiometry. The antiproliferative activity of the new 5-FU derivatives was assessed in vitro on SK-MEL-28 and WM793 human melanoma cell lines in 2D culture as well as on A549 human lung carcinoma, MDA-MB-231 breast adenocarcinoma, LL24 normal lung tissue, and HMF normal breast tissue as a multicellular 3D spheroid model cultured in standard (static) conditions and with the use of microfluidic systems, which to a great extent resembles the in vivo environment. In all cases, new mutual prodrugs showed a higher cytotoxic activity toward cancer models and lower to normal cell models than the parent 5-FU itself.

The Impact of Omitting 5-FU Bolus From mFOLFOX6 Chemotherapy Regimen on Hematological Adverse Events Among Patients With Metastatic Colorectal Cancer

Background

Metastatic colorectal cancer (mCRC) is often treated with a mFOLFOX6 regimen. The 5-fluorouracil (5-FU) bolus is often omitted from the regimen to reduce the risk of hematological adverse events (AEs) in patients with poor performance status. We aimed to investigate the incidence of hematological AEs in Asian patients with mCRC who were treated with the mFOLFOX6 with and without 5-FU bolus dosing.

Methods

This retrospective chart review was conducted at King Chulalongkorn Memorial Hospital, Thailand from June 2021 to June 2022. The primary endpoints were hematological AEs. Secondary endpoints were any AEs. The comparison of continuous data was conducted with an independent t-test. The Chi-squared test was used to compare categorical data.

Results

From 110 patients, we found that hematological and non-hematological AEs of any grade in the two groups were not significantly different. However, patients in the bolus arm had a significantly lower absolute neutrophil count (ANC) than those in the non-bolus arm (mean difference = 43.13 (95% confidence interval (CI): 20.74, 65.51), P-value = 0.0002). A subgroup analysis in patients who received first-line treatment with mFOLFOX6 showed that the bolus arm had a significantly lower ANC (mean difference = 46.01 (95% CI: 19.99, 72.03), P-value = 0.0007).

Conclusions

mCRC patients who were treated with bolus 5-FU had lower ANC. The 5-FU bolus omission from the mFOLFOX6 regimen may be required in patients with a high risk of neutropenia.

Martynoside rescues 5-fluorouracil-impaired ribosome biogenesis by stabilizing RPL27A

Martynoside (MAR), a bioactive component in several well-known tonic traditional Chinese herbs, exhibits pro-hematopoietic activity during 5-fluorouracil (5-FU) treatment. However, the molecular target and the mechanism of MAR are poorly understood. Here, by adopting the mRNA display with a library of even-distribution (md-LED) method, we systematically examined MAR-protein interactions in vitro and identified the ribosomal protein L27a (RPL27A) as a key cellular target of MAR. Structural and mutational analysis confirmed the specific interaction between MAR and the exon 4,5-encoded region of RPL27A. MAR attenuated 5-FU-induced cytotoxicity in bone marrow nucleated cells, increased RPL27A protein stability, and reduced the ubiquitination of RPL27A at lys92 (K92) and lys94 (K94). Disruption of MAR binding at key residues of RPL27A completely abolished the MAR-induced stabilization. Furthermore, by integrating label-free quantitative ubiquitination proteomics, transcriptomics, and ribosome function assays, we revealed that MAR restored RPL27A protein levels and thus rescued ribosome biogenesis impaired by 5-FU. Specifically, MAR increased mature ribosomal RNA (rRNA) abundance, prevented ribosomal protein degradation, facilitated ribosome assembly, and maintained nucleolar integrity. Collectively, our findings characterize the target of a component of Chinese medicine, reveal the importance of ribosome biogenesis in hematopoiesis, and open up a new direction for improving hematopoiesis by targeting RPL27A.

Dissociative electron attachment to gold(I)-based compounds: 4,5-dichloro-1,3-diethyl-imidazolylidene trifluoromethyl gold(I)

With the use of proton-NMR and powder XRD (XRPD) studies, the suitability of specific Au-focused electron beam induced deposition (FEBID) precursors has been investigated with low electron energy, structure, excited states and resonances, structural crystal modifications, flexibility, and vaporization level. 4,5-Dichloro-1,3-diethyl-imidazolylidene trifluoromethyl gold(I) is a compound that is a uniquely designed precursor to meet the needs of focused electron beam-induced deposition at the nanostructure level, which proves its capability in creating high purity structures, and its growing importance in other AuIm_x and AuCl_nB (where x and n are the number of radicals, B = CH, CH₃, or Br) compounds in the radiation cancer therapy increases the efforts to design more suitable bonds in processes of SEM (scanning electron microscopy) deposition and in gas-phase studies. The investigation performed of its powder shape using the XRPD XPERT³ panalytical diffractometer based on CoK_α lines shows changes to its structure with change in temperature, level of vacuum, and light; the sensitivity of this compound makes it highly interesting in particular to the radiation research. Used in FEBID, though its smaller number of C, H, and O atoms has lower levels of C contamination in the structures and on the surface, it replaces these bonds with C-Cl and C-N bonds that have lower bond-breaking energy. However, it still needs an extra purification step in the deposition process, either H₂O, O₂, or H jets.

Development and cytotoxicity evaluation of multiple nanoemulsions for oral co-delivery of 5-fluorouracil and short chain triglycerides for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world, but current chemotherapy options are limited due to adverse effects and low oral bioavailability of drugs. In this study, we investigated the obtainment parameters and composition of new multiple nanoemulsions (MN) based on microemulsions for oral co-delivery of 5-fluorouracil (5FU) and short-chain triglycerides (SCT, either tributyrin or tripropionin). The area of microemulsion formation was increased from 14% to 38% when monocaprylin was mixed with tricaprylin as oil phase. Addition of SCT reduced this value to 24-26%. Using sodium alginate aqueous dispersion as internal aqueous phase (to avoid phase inversion) did not further affected the area but increased microemulsion viscosity by 1.5-fold. To obtain the MN, selected microemulsions were diluted in an external aqueous phase; droplet size was 500 nm and stability improved using polyoxyethylene (den Besten et al., 2013) oleyl ether at 1-2.5% as surfactant in the external phase and a dilution ratio of 1:1 (v/v). 5FU in vitro release could be better described by the Korsmeyer-Peppas model. No pronounced changes in droplet size were observed when selected MNs were incubated in buffers mimicking gastrointestinal fluids. The 5FU cytotoxicity in monolayer cell lines presenting various mutations was influenced by its incorporation in the nanocarrier, presence of SCT and cell mutation status. The MNs selected reduced the viability of tumor spheroids (employed as 3D tumor models) by 2.2-fold compared to 5FU solution and did not affect the survival of the G. mellonella, suggesting effectiveness and safety.

Discovery of SI 1/20 and SI 1/22 as Mutual Prodrugs of 5-Fluorouracil and Imidazole-Based Heme Oxygenase 1 Inhibitor with Improved Cytotoxicity in DU145 Prostate Cancer Cells

In this work, we extend the concept of 5-fluorouracil/heme oxygenase 1 (5-FU/HO-1) inhibitor hybrid as an effective strategy for enhancing 5-FU-based anticancer therapies. For this purpose, we designed and synthesized new mutual prodrugs, named SI 1/20 and SI 1/22, in which the two active parent drugs (i. e., 5-FU and an imidazole-based HO-1 inhibitor) were connected through an easily cleavable succinic linker. Experimental hydrolysis rate, and in silico ADMET predictions were indicative of good drug-likeness and pharmacokinetic properties. Novel hybrids significantly reduced the viability of prostate DU145 cancer cells compared to the parent compounds 5-FU and HO-1 inhibitor administered alone or in combination. Interestingly, both compounds showed statistically significant lower toxicity, than 5-FU at the same dose, against non-tumorigenic human benign prostatic hyperplasia (BPH-1) cell line. Moreover, the newly synthesized mutual prodrugs inhibited the HO-1 activity both in a cell-free model and in vitro, as well as downregulated the HO-1 expression and increased the reactive oxygen species (ROS) levels.

Application of nanotechnology in reversing therapeutic resistance and controlling metastasis of colorectal cancer

Colorectal cancer (CRC) is the most common digestive malignancy across the world. Its first-line treatments applied in the routine clinical setting include surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy. However, resistance to therapy has been identified as the major clinical challenge that fails the treatment method, leading to recurrence and distant metastasis. An increasing number of studies have been attempting to explore the underlying mechanisms of the resistance of CRC cells to different therapies, which can be summarized into two aspects: (1) The intrinsic characters and adapted alterations of CRC cells before and during treatment that regulate the drug metabolism, drug transport, drug target, and the activation of signaling pathways; and (2) the suppressive features of the tumor microenvironment (TME). To combat the issue of therapeutic resistance, effective strategies are warranted with a focus on the restoration of CRC cells’ sensitivity to specific treatments as well as reprogramming impressive TME into stimulatory conditions. To date, nanotechnology seems promising with scope for improvement of drug mobility, treatment efficacy, and reduction of systemic toxicity. The instinctive advantages offered by nanomaterials enable the diversity of loading cargoes to increase drug concentration and targeting specificity, as well as offer a platform for trying the combination of different treatments to eventually prevent tumor recurrence, metastasis, and reversion of therapy resistance. The present review intends to summarize the known mechanisms of CRC resistance to chemotherapy, radiotherapy, immunotherapy, and targeted therapy, as well as the process of metastasis. We have also emphasized the recent application of nanomaterials in combating therapeutic resistance and preventing metastasis either by combining with other treatment approaches or alone. In summary, nanomedicine is an emerging technology with potential for CRC treatment; hence, efforts should be devoted to targeting cancer cells for the restoration of therapeutic sensitivity as well as reprogramming the TME. It is believed that the combined strategy will be beneficial to achieve synergistic outcomes contributing to control and management of CRC in the future.

Myeloid-derived suppressor cells in head and neck squamous cell carcinoma

Myeloid-derived suppressor cells (MDSCs), which originated from hematopoietic stem cells, are heterogeneous population of cells that have different differentiation patterns and widely presented in tumor microenvironment. For tumor research, myeloid suppressor cells have received extensive attention since their discovery due to their specific immunosuppressive properties, and the mechanisms of immunosuppression and therapeutic approaches for MDSCs have been investigated in a variety of different types of malignancies. To improve the efficacy of treatment for head and neck squamous cell carcinoma (HNSCC), a disease with a high occurrence, immunotherapy has gradually emerged in after traditional surgery and subsequent radiotherapy and chemotherapy, and has made some progress. In this review, we introduced the mechanisms on the development, differentiation, and elimination of MDSCs and provided a detailed overview of the mechanisms behind the immunosuppressive properties of MDSCs. We summarized the recent researches on MDSCs in HNSCC, especially for targeting-MDSCs therapy and combination with other types of therapy such as immune checkpoint blockade (ICB). Furthermore, we looked at drug delivery patterns and collected the current diverse drug delivery systems for the improvement that contributed to therapy against MDSCs in HNSCC. Most importantly, we made possible outlooks for the future research priorities, which provide a basis for further study on the clinical significance and therapeutic value of MDSCs in HNSCC.

Evaluation of the Effect of Grape Seed Extract (GSE) on Oral Mucositis in Patients with Head and Neck Radiotherapy History- A Randomized Clinical Trial

Background: Mucositis is one of the most important complications of radiotherapy. Some factors such as type of treatment and degree of patient sensitivity affect mucositis occurrence. Objective: This research was implemented to evaluate the effect of grape seed extract on radiation-induced mucositis. Methods: This research is a double-blinded randomized clinical trial implemented on 78 patients undergoing head and neck radiotherapy in the oncology ward of Imam Reza Hospital of Tabriz. The patients were randomly divided into 2 groups, the intervention, and the control group. Each group included 39 patients. The intervention group used 2% grape seed extract mouthwashes and the control group used placebo mouthwashes. The mouthwashes were used 3 times a day for 2 weeks. For statistical analysis of collected data, SPSS 20 software was applied. Results: The results showed that according to the Friedman test, on the 10th and 14th days, mucositis grade and incidence had a significant difference between the intervention and control groups. Conclusions: The findings indicated that grape seed extract mouthwash in preventing radiation-induced mucositis was more effective than a placebo. Thus, this agent can be recommended as an appropriate medication to eliminate oral mucositis symptoms.

Identification of DPYD variants and estimation of uracil and dihydrouracil in a healthy Indian population

Aim: This study aimed to identify DPYD variants and the related but previously unexplored phenotype (plasma uracil, dihydrouracil [DHU], and the DHU-to-uracil ratio) in a healthy adult Indian population. Methods: Healthy adult volunteers (n = 100) had their uracil and DHU levels measured and were genotyped for selected variants. Results: Among the nine variants studied, c.1906-14763G>A and c.85T>C were the most prevalent. Participants with any of the variants except for c.85T>C and c.1627A>G had a significantly lower DHU-to-uracil ratio and those with c.1905+1G>A variant had significantly increased uracil concentration compared with wild type. Conclusion: Participants with five variants were identified as having altered phenotypic measures, and 40% of the intermediate metabolizers had their phenotype in the terminal population percentiles.

Rational Design, Synthesis, and Biological Evaluation of Novel S1PR2 Antagonists for Reversing 5-FU-Resistance in Colorectal Cancer

Resistance to 5-FU reduces its clinical efficacy for the treatment of colorectal cancer. Sphingosine-1-phosphate receptor 2 (S1PR2) has emerged as a potential target to reverse 5-FU-resistance by inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). In this study, 38 novel S1PR2 antagonists based on aryl urea structure were designed and synthesized, and the structure-activity relationship was investigated based on the S1PR2 binding assay. Representative compound 43 potently interacts with S1PR2 with a K_D value of 0.73 nM. It displays potent 5-FU resensitizing activity in multiple 5-FU-resistant tumor cell lines, particularly in SW620/5-FU (EC₅₀ = 1.99 ± 0.03 μM) but shows no cytotoxicity in the normal colon cell line NCM460 up to 1000 μM. Moreover, 43 significantly enhances the antitumor efficacy of 5-FU in the SW620/5-FU animal model. These data suggest that 43 could be a novel lead compound for developing a 5-FU resensitizing agent.

Drug Resistance in Colorectal Cancer: From Mechanism to Clinic

Colorectal cancer (CRC) is one of the leading causes of death worldwide. The 5-year survival rate is 90% for patients with early CRC, 70% for patients with locally advanced CRC, and 15% for patients with metastatic CRC (mCRC). In fact, most CRC patients are at an advanced stage at the time of diagnosis. Although chemotherapy, molecularly targeted therapy and immunotherapy have significantly improved patient survival, some patients are initially insensitive to these drugs or initially sensitive but quickly become insensitive, and the emergence of such primary and secondary drug resistance is a significant clinical challenge. The most direct cause of resistance is the aberrant anti-tumor drug metabolism, transportation or target. With more in-depth research, it is found that cell death pathways, carcinogenic signals, compensation feedback loop signal pathways and tumor immune microenvironment also play essential roles in the drug resistance mechanism. Here, we assess the current major mechanisms of CRC resistance and describe potential therapeutic interventions.

Complexation of 5-Fluorouracil with β-Cyclodextrin and Sodium Dodecyl Sulfate: A Useful Tool for Encapsulating and Removing This Polluting Drug

The formation of complexes of the drug 5-fluorouracil (5-FU) with β-cyclodextrin (β-CD) and sodium dodecyl sulphate (SDS) was studied through experimental measurements of the ternary mutual diffusion coefficients (D11, D22, D12, and D21) for the systems {5-FU (component 1) + β-CD (component 2) + water} and {5-FU (component 1) + SDS (component 2) + water} at 298.15 K and at concentrations up to 0.05 mol dm−3 by using the Taylor dispersion method, with the objective of removing this polluting drug from the residual systems in which it was present. The results found showed that a coupled diffusion of 5-FU occurred with both β-CD and SDS, as indicated by the nonzero values of the cross-diffusion coefficients, D12 and D21, as a consequence of the complex formation between 5-FU and the β-CD or SDS species. That is, 5-FU was solubilized (encapsulated) by both carriers, although to a greater extent with SDS (K = 20.0 (±0.5) mol−1 dm3) than with β-CD (K = 10.0 (±0.5) mol−1 dm3). Values of 0.107 and 0.190 were determined for the maximum fraction of 5-FU solubilized with β-CD and SDS (at concentrations above its CMC), respectively. This meant that SDS was more efficient at encapsulating and thus removing the 5-FU drug.

Protective effect of polysaccharides isolated from the seeds of Cuscuta chinensis Lam. on 5-fluorouracil-induced intestinal mucositis in mice

Purpose:

To evaluate the protective effect of Cuscuta chinensis Lam. polysaccharides (PCCL) on 5-fluorouracil-(5-FU)-induced intestinal mucositis (IM) in mice.

Methods:

PCCL was orally administered at a dose of 20 mg·kg^–1 for 7 days and its protective effect on 5-FU-induced IM (5-FU, 50 mg·kg^–1 for 5 days) was evaluated by monitoring changes in body weight, degree of diarrhea, levels of tissue inflammatory factors (tumor necrosis factor α, interleukin 6, and interleukin 1β levels), apoptosis rates, and the expression levels of caspase-3, Bax and Bcl-2.

Results:

The severity of mucosal injury (as reflected by body weight changes, degree of diarrhea, height of villi, and damage to crypts) was significantly attenuated by PCCL administration. PCCL also reduced the levels of tissue inflammatory factors, the apoptosis rate, and the expression of caspase-3 and Bax, and increased Bcl-2 expression.

Conclusions:

PCCL administration may be significantly protective against 5-FU-induced IM by inhibiting apoptosis and regulating the abnormal inflammation associated with it.

Folate Conjugated Polyethylene Glycol Probe for Tumor-Targeted Drug Delivery of 5-Fluorouracil

A targeted delivery system is primarily intended to carry a potent anticancer drug to specific tumor sites within the bodily tissues. In the present study, a carrier system has been designed using folic acid (FA), bis-amine polyethylene glycol (PEG), and an anticancer drug, 5-fluorouracil (5-FU). FA and PEG were joined via an amide bond, and the resulting FA-PEG-NH2 was coupled to 5-FU producing folate-polyethylene glycol conjugated 5-fluorouracil (FA-PEG-5-FU). Spectroscopic techniques (UV-Vis, 1HNMR, FTIR, and HPLC) were used for the characterization of products. Prodrug (FA-PEG-5-FU) was analyzed for drug release profile (in vitro) up to 10 days and compared to a standard anticancer drug (5-FU). Folate conjugate was also analyzed to study its folate receptors (FR) mediated transport and in vitro cytotoxicity assays using HeLa cancer cells/Vero cells, respectively, and antitumor activity in tumor-bearing mice models. Folate conjugate showed steady drug release patterns and improved uptake in the HeLa cancer cells than Vero cells. Folate conjugate treated mice group showed smaller tumor volumes; specifically after the 15th day post-treatment, tumor sizes were decreased significantly compared to the standard drug group (5-FU). Molecular docking findings demonstrated importance of Trp138, Trp140, and Lys136 in the stabilization of flexible loop flanking the active site. The folic acid conjugated probe has shown the potential of targeted drug delivery and sustained release of anticancer drug to tumor lesions with intact antitumor efficacy.

A Review of Potential Role of Capsule Endoscopy in the Work-Up for Chemotherapy-Induced Diarrhea

Chemotherapy-induced diarrhea (CID) is a common, severe side effect of chemotherapy, immunotherapy, and targeted therapy. Because patients are more prone to continuing chemotherapy if they do not suffer from CID, appropriate diagnosis and monitoring of this disease are essential. However, suitable monitoring methods are yet to be developed. To date, several studies have shown that small-bowel capsule endoscopy (SBCE) is useful in visualizing the entire small intestinal mucosa and detecting small intestinal abnormalities, including bleeding, malignant tumors, and mucosal injury, associated with the use of nonsteroidal anti-inflammatory drugs and low-dose aspirin. Currently, limited studies have evaluated the small intestinal mucosa using SBCE in patients receiving fluoropyrimidine-based chemotherapy or immune checkpoint inhibitors. These studies have reported that small intestinal mucosal injury is common in patients with severe fluoropyrimidine-induced diarrhea. SBCE might be a useful screening method for the early detection of enterocolitis induced by immune checkpoint inhibitors. SBCE may be a powerful tool for the diagnosis and monitoring of CID, and understanding its indication, contraindication, and capsule-retention risk for each patient is important for clinicians.

Novel 5-fluorouracil sensitizers for colorectal cancer therapy: Design and synthesis of S1P receptor 2 (S1PR2) antagonists

Sphingosine-1-phosphate receptor 2 (S1PR2) has been identified as a brand-new GPCR target for designing antagonists to reverse 5-FU resistance. We herein report the structural optimization and structure-activity relationship of JTE-013 derivatives as S1PR2 antagonists. Compound 9d was the most potent S1PR2 antagonist (K_D = 34.8 nM) among developed compounds. Here, compound 9d could significantly inhibit the expression of dihydropyrimidine dehydrogenase (DPD) to reverse 5-FU-resistance in HCT116^DPD and SW620/5-FU cells. Further mechanism studies demonstrated that compound 9d not only inhibited S1PR2 but also affected the transcription of S1PR2. In addition, compound 9d also showed acceptable selectivity to normal cells (NCM460). Importantly, compound 9d with suitable pharmacokinetic properties could significantly reverse 5-FU-resistance in the HCT116^DPD and SW620/5-FU xenograft models without obvious toxicity, in which the inhibition rates of 5-FU were increased from 23.97% to 65.29% and 27.23% to 60.81%, respectively. Further immunohistochemistry and western blotting analysis also demonstrated that compound 9d significantly decreases the expression of DPD in tumor and liver tissues. These results indicated that compound 9d is a promising lead compound to reverse 5-FU-resistance for colorectal cancer therapy.

Correlation of PIK3CA mutation with programmed death ligand-1 (PD-L1) expression and their clinicopathological significance in colorectal cancer

Background

The prognostic significance of PIK3CA mutations in colorectal cancer (CRC) remains controversial. Recently, an association between programmed death ligand-1 (PD-L1) and PIK3CA mutations has been reported. The study presented here was conducted to investigate the effect of PIK3CA mutations on the prognosis of CRC patients and the association between PIK3CA mutations and PD-L1.

Methods

PIK3CA mutations were analyzed by targeted next-generation sequencing using formalin-fixed paraffin-embedded specimens from 224 primary CRC patients. PD-L1 expression was evaluated by immunohistochemical staining.

Results

PIK3CA mutations and PD-L1 expression were detected in 21.4% and 10.3% of CRC patients, respectively. PIK3CA mutations were significantly correlated with right-side colon cancer (P=0.011) and were correlated inversely with lymph node metastasis (P=0.026), distant metastasis (P=0.047), and high TNM stage (P=0.036). In univariate analysis, PIK3CA mutations were correlated with longer relapse-free survival in CRC patients. PD-L1 expression was correlated significantly with PIK3CA mutations (P<0.001).

Conclusions

PIK3CA mutations were associated with favorable prognostic factors, longer relapse-free survival, and expression of PD-L1. Further investigation is needed to identify whether PIK3CA mutations are a good prognostic factor. Additionally, further studies are needed to understand the mechanisms behind the correlation between PIK3CA mutations and PD-L1 expression.

Strengths and Weaknesses of Cell Synchronization Protocols Based on Inhibition of DNA Synthesis

Synchronous cell populations are commonly used for the analysis of various aspects of cellular metabolism at specific stages of the cell cycle. Cell synchronization at a chosen cell cycle stage is most frequently achieved by inhibition of specific metabolic pathway(s). In this respect, various protocols have been developed to synchronize cells in particular cell cycle stages. In this review, we provide an overview of the protocols for cell synchronization of mammalian cells based on the inhibition of synthesis of DNA building blocks-deoxynucleotides and/or inhibition of DNA synthesis. The mechanism of action, examples of their use, and advantages and disadvantages are described with the aim of providing a guide for the selection of suitable protocol for different studied situations.

Plasma-enhanced protein patterning in a microfluidic compartmentalized platform for multi-organs-on-chip: a liver-tumor model

A microfluidic technique is presented for micropatterning protein domains and cell cultures within permanently bonded organs-on-chip devices. This method is based on the use of polydimethylsiloxane layers coupled with the plasma ablation technique for selective protein removal. We show how this technique can be employed to generate a multi-organin vitromodel directly within a microscale platform suitable for pharmacokinetic-based drug screening. We miniaturized a liver model based on micropatterned co-cultures in dual-compartment microfluidic devices. The cytotoxic effect of liver-metabolized Tegafur on colon cancer cell line was assessed using two microfluidic devices where microgrooves and valves systems are used to model drug diffusion between culture compartments. The platforms can reproduce the metabolism of Tegafur in the liver, thus killing colon cancer cells. The proposed plasma-enhanced microfluidic protein patterning method thus successfully combines the ability to generate precise cell micropatterning with the intrinsic advantages of microfluidics in cell biology.

Chitosan-glucuronic acid conjugate coated mesoporous silica nanoparticles: A smart pH-responsive and receptor-targeted system for colorectal cancer therapy

Glycosylated pH-sensitive mesoporous silica nanoparticles (MSNs) of capecitabine (CAP) were developed for targeting colorectal cancer. The MSNs possessed an average pore diameter of 8.12 ± 0.43 nm, pore volume of 0.73 ± 0.21 cm3/g, and particle size of 245.24 ± 5.75 nm. A high loading of 180.51 ± 5.23 mg/g attributed to the larger pore volume was observed. The surface of the drug-loaded MSNs were capped with chitosan-glucuronic acid (CHS-GCA) conjugate to combine two strategies viz. pH-sensitive, and lectin receptor mediated uptake. In vitro studies demonstrated a pH-sensitive and controlled release of CAP which was further enhanced in the presence of rat caecal content. Higher uptake of the (CAP-MSN)CHS-GCA was observed in HCT 116 cell lines. The glycosylated nanoparticles revealed reduction in the tumors, aberrant crypt foci, dysplasia and inflammation, and alleviation in the toxic features. This illustrated that the nanoparticles showed promising antitumor efficacy with reduced toxicity and may be used as a effective carrier against cancer.

Synthesis, biological evaluation and docking studies of 1,2,4-oxadiazole linked 5-fluorouracil derivatives as anticancer agents

BACKGROUND

1,2,4-oxadiazole derivatives exhibited significant anti-cancer activity when they were evaluated, against human cancer cell lines. They also showed anti-inflammatory, analgesic, diabetic, immunosuppressive, α,β3-receptor antagonist, antimicrobial, anti-helminthic, histamine-H3 and antiparasitic properties. A pyrimidine analog, 5 fluoro-uracil is a chemotherapeutic drug used for treating multiple solid malignant tumors. But its application is limited, as it has side effects like low bioavailability and high toxicity. Molecular docking is an exemplary tool, helps in identifying target and designing a drug containing high bio-availability and minimum toxicity.

RESULTS

A set of 1,2,4-oxadiazole linked 5-fluoruracil derivatives (7a-j) were synthesized and their structures were confirmed by 1HNMR, 13CNMR and Mass spectral analysis. Further, these compounds were investigated for their anticancer activity towards a panel of four human cancer cell lines such as (MCF-7, MDA MB-231), lung cancer (A549) and prostate cancer (DU-145) by using MTT method. Among them, compounds 7a, 7b, 7c, 7d and 7i demonstrated more promising anticancer activity than standard.

CONCLUSION

Synthesized derivatives (7a-j) of 1,2,4-oxadiazole linked 5-fluorouracil and investigated for their anticancer activity towards a panel of four human cancer cell lines.

Oral drugs in the treatment of metastatic colorectal cancer

Colorectal cancer (CRC) is one of the most common forms of cancer, with an estimated 1.36 million new cases and almost 700,000 deaths annually. Approximately 21% of patients with CRC have metastatic disease at diagnosis. The objective of this article is to review the literature on the efficacy and safety of oral drugs available for the treatment of metastatic colorectal cancer (mCRC). Several such drugs have been developed, and fluoropyrimidines are the backbone of chemotherapy in this indication. They exert their antitumour activity by disrupting the synthesis and function of DNA and RNA. Oral fluoropyrimidines include prodrugs capecitabine, tegafur, eniluracil/5-fluorouracil, tegafur/uracil, tegafur/gimeracil/oteracil and trifluridine/tipiracil (FTD/TPI). Oral drugs offer several advantages over injectable formulations, including convenience, flexibility, avoidance of injection-related adverse events (AEs) and, in some circumstances, lower costs. However, oral drugs may not be suitable for patients with gastrointestinal obstruction or malabsorption, they may result in reduced treatment adherence and should not be co-administered with drugs that interfere with absorption or hepatic metabolism. Oral fluoropyrimidines such as capecitabine, as monotherapy or in combination with oxaliplatin, irinotecan or bevacizumab, are as effective as intravenous 5-fluorouracil (5-FU) in first-line treatment of mCRC. Other oral fluoropyrimidines, such as FTD/TPI, are effective in patients with mCRC who are refractory, intolerant or ineligible for 5-FU. In addition, oral fluoropyrimidines are used in adjuvant treatment of mCRC. Regorafenib is an oral multikinase inhibitor used in patients in whom several previous lines of therapy have failed. Frequent AEs associated with oral drugs used in the treatment of CRC include hand-foot syndrome and gastrointestinal and haematological toxicities.

CD15+ tumor infiltrating granulocytic cells can predict recurrence and their depletion is accompanied by good responses to S-1 with oral cancer

BACKGROUND

It has been reported in oral squamous cell carcinoma (OSCC) that myeloid-derived suppressor cells infiltrate tumor tissues. This study examined whether S-1 chemotherapy changes immune cell populations in the tumor microenvironment.

METHODS

We examined 71 patients with of OSCC, including 51 patients who received preoperative S-1 chemotherapy. Immunohistochemistry for PD-L1, CD8, forkhead box protein 3 (FOXP3), and CD15 was performed using biopsy and resected specimens.

RESULTS

The numbers of CD8⁺ , FOXP3⁺ , and CD15⁺ cells in resected specimens were significantly decreased by S-1 chemotherapy. The reduction of the proportion of CD15⁺ cells significantly differed between responders and nonresponders. Most responders were distributed into the group with low PD-L1 expression and a low density of CD8⁺ cells before chemotherapy. Furthermore, many patients with recurrence exhibited a high density of CD15⁺ cells in biopsy specimens.

CONCLUSION

Preoperative S-1 chemotherapy can potentially improve prognosis by reducing CD15⁺ cells in the tumor microenvironment.

The alterations of microbiota and pathological conditions in the gut of patients with colorectal cancer undergoing chemotherapy

Colorectal cancer (CRC) has become a serious threat to human life and health. Most patients are diagnosed at the late stage of advanced CRC, resulting in losing their best opportunity for surgical treatment. Chemotherapy plays a crucial role in the control and treatment of advanced CRC. However, the cytotoxicity of chemotherapeutic drugs can easily cause the imbalance of gut flora, damage the barrier of the gastrointestinal mucosa, and mediate mucosal inflammation of the digestive tract, which is called "gastrointestinal mucositis." This mucositis can affect the quality of life of the host and even threaten their lives. Several studies reported the association between chemotherapy-mediated gastrointestinal mucositis in CRC and gut dysbiosis. However, the underlying mechanisms of this association are still unclear. The alternative or complementary treatments to reshape gut microbiota and slow down the side effects of chemotherapy have shown the improvement of gastrointestinal mucositis following chemotherapy in the CRC condition. This review will summarize and discuss the evidence of the association between chemotherapy-mediated gastrointestinal mucositis in CRC and altered gut microbiota from in vivo and clinical studies. The possible mechanisms of gastrointestinal mucositis, including the destruction of the gastrointestinal mucosal barrier, the induction of gut dysbiosis, and histopathological changes in the gut of CRC with chemotherapy will be illustrated. In addition, the nonpharmacological interventions and phytochemical extracts by using the manipulation of the microbial population for therapeutic purposes for relieving side effects of chemotherapy as well as a cancer treatment would be summarized and discussed in this review.

Parallel G-quadruplex Structures Increase Cellular Uptake and Cytotoxicity of 5-Fluoro-2'-deoxyuridine Oligomers in 5-Fluorouracil Resistant Cells

Fluoropyrimidines, such as 5-fluorouracil (5-FU) and related prodrugs have been considered first-line chemotherapy agents for the treatment of colorectal cancer. However, poor specificity and tumor cell resistance remain major limiting bottlenecks. G-quadruplexes, have been suggested as preferred nanostructures for enhancing cellular uptake mediated by G-quadruplex binding proteins which are abundant at the membranes of some tumor cells. In the current study, we propose a new strategy to deliver 5-fluoro-2′-deoxyuridine (5-FdU) monophosphate, the main active drug from 5-FU derivatives that may circumvent the cellular mechanisms of FU-resistant cancer cells. Two G-quadruplexes delivery systems containing four and six G-tetrads ((TG₄T) and (TG₆T)) linked to a FdU oligonucleotide were synthesized. Biophysical studies show that the G-quadruplex parallel structures are not affected by the incorporation of the 5 units of FdU at the 5’-end. Internalization studies confirmed the ability of such G-quadruplex nanostructures to facilitate the transport of the FdU pentamer and increase its cytotoxic effect relative to conventional FU drug in FU-resistant colorectal cancer cells. These results suggest that FdU oligomers linked to G-quadruplex parallel sequences may be a promising strategy to deliver fluoropyrimidines to cancer cells.

Phase I dose escalation study of sorafenib plus S-1 for advanced solid tumors

S-1, an oral pyrimidine fluoride-derived agent, is effective against various cancers. Sorafenib, an oral multikinase inhibitor, was found to prolong the survival of various cancers and enhance the cytotoxicity of chemotherapeutic agents. We conducted a phase I dose escalation study to determine dose-limiting toxicity (DLT) and maximal tolerated dose (MTD) of S-1 when combined with sorafenib for refractory solid tumors. Eligible patients received escalating doses (30, 35, and 40 mg/m² bid) of S-1 Day 1 (D1)-D14 and continuous sorafenib 400 mg bid from cycle 1 D8 every 21 days in a standard 3 + 3 study design. Primary endpoint was MTD. Thirteen patients were enrolled between May 2010 and Feb 2012. DLT developed in two (one grade 3 erythema and one prolonged grade 2 hand-foot-skin reaction) of the 6 patients at 35 mg/m² dose level. One pancreatic neuroendocrine tumor (pNET) patient achieved a durable partial response (27.9 months). Four colon cancer patients had stable disease and 3 of them had progression-free survival greater than 6 months. This study determined the recommended (MTD) S-1 dose of 30 mg/m² bid for this regimen. This result warrants further phase II studies for advanced pNET and colon cancer to evaluate the efficacy of this combination.

Comparison of capecitabine-based regimens with platinum-based regimens in Chinese triple-negative breast cancer patients with liver metastasis

Background

Capecitabine-based chemotherapy (CBC) presents potential value in patients with liver metastasis; platinum-based chemotherapy (PBC) has shown promising benefit in patients with triple-negative breast cancer (TNBC). For TNBC patients with liver metastasis, which treatment strategy is better remains to be further studied. The aim of this study was to report the first real-world data evaluating the efficacy and safety of PBC versus CBC in the first-line treatment in Chinese TNBC patients with liver metastasis.

Methods

TNBC patients with liver metastasis pretreated with anthracyclines/taxanes in 4 institutions of China between January 2010 and December 2019 were included. Objective response rate (ORR), overall survival, treatment pattern, and toxicity profile were assessed between PBC and CBC groups.

Results

A total of 59 TNBC patients with liver metastasis were identified. Among these, 33 were treated with PBC and 26 were treated with CBC. The ORR was higher in the CBC group than in the PBC group (57.7% versus 30.3%, P=0.035). Median overall survival was also greatly improved (19.2 versus 14.4 months, P=0.041). Docetaxel/cisplatin was more likely to be used for PBC, and paclitaxel/capecitabine was the main regimen for CBC. Multivariable Cox regression analysis indicated that CBC was an independent predictor for overall survival after adjustment for baseline factors including age, tumor size, nodal status, prior anthracyclines/taxanes use, and tumor grade (odds ratio =0.51; 95% confidence interval, 0.27-0.98; P=0.042). Adverse events were not different except gastrointestinal tract toxicities, hand-foot syndrome and hematologic toxicity.

Conclusions

For TNBC patients with liver metastasis, capecitabin-based chemotherapy might be more suitable than the platinum-based regimen in the first-line treatment, as measured by objective response rate and overall survival. Further large-scale studies are warranted.