A Rodent Model of Human-Dose-Equivalent 5-Fluorouracil: Toxicity in the Liver, Kidneys, and Lungs

5-Fluorouracil (5-FU) is a chemotherapy drug widely used to treat a range of cancer types, despite the recurrence of adverse reactions. Therefore, information on its side effects when administered at a clinically recommended dose is relevant. On this basis, we examined the effects of the 5-FU clinical treatment on the integrity of the liver, kidneys, and lungs of rats. For this purpose, 14 male Wistar rats were divided into treated and control groups and 5-FU was administered at 15 mg/kg (4 consecutive days), 6 mg/kg (4 alternate days), and 15 mg/kg on the 14th day. On the 15th day, blood, liver, kidney, and lung samples were collected for histological, oxidative stress, and inflammatory evaluations. We observed a reduction in the antioxidant markers and an increase in lipid hydroperoxides (LOOH) in the liver of treated animals. We also detected elevated levels of inflammatory markers, histological lesions, apoptotic cells, and aspartate aminotransferase. Clinical treatment with 5-FU did not promote inflammatory or oxidative alterations in the kidney samples; however, histological and biochemical changes were observed, including increased serum urea and uric acid. 5-FU reduces endogenous antioxidant defenses and increases LOOH levels in the lungs, suggesting oxidative stress. Inflammation and histopathological alterations were also detected. The clinical protocol of 5-FU promotes toxicity in the liver, kidneys, and lungs of healthy rats, resulting in different levels of histological and biochemical alterations. These results will be useful in the search for new adjuvants to attenuate the adverse effects of 5-FU in such organs.

Development of a Two-Layered Sheet Formulation of 5-Fluorouracil for Application to Rat's Livers to Ensure Controlled Release and Local Drug Disposition

This study aimed to develop a new and effective application form for the liver surface. We designed a two-layered sheet for the controlled release and local disposition of the anticancer drug, 5-fluorouracil (5-FU), without leakage into the peritoneal cavity. We employed poly(lactic-co-glycolic acid) (PLGA) and hydroxypropyl cellulose (HPC) to form two-layered sheets by attaching a cover sheet and a drug-containing sheet. The prepared two-layered sheets released 5-FU constantly for up to 14 d without any significant leakage from the cover side in vitro. Furthermore, we have applied sheets containing 5-FU to the rat liver surface in vivo. Notably, 5-FU could be detected in the liver attachment region even 28 d after application. The distribution ratio of 5-FU in the attachment region compared to the other liver lobes varied among the sheet formulations with different additive HPC compositions. The area under the liver concentration-time curve (AUC) of 5-FU in the attachment region from 0 to 28 d was the highest in the case of HPC 2% (w/w). This is probably due to the enhanced 5-FU released amount and controlled absorption rate from the liver surface by released HPC. No critical toxic effects were evident by the application of the two-layered sheets from the body weight change and alanine aminotransferase/aspartate aminotransferase (ALT/AST) activities. Consequently, the possible advantage of the two-layered sheets for prolonged retention of a drug in a specific region in the liver was clarified.

Novel 5-Fluorouracil Carbonate-Loaded Liposome: Preparation, In Vitro, and In Vivo Evaluation as an Antitumor Agent

5-Fluorouracil (5-FU) is a chemotherapeutic drug against many types of cancers, especially colorectal cancer. However, its short plasma half-life and serious adverse reactions limit its wide clinical applications. To overcome these shortcomings, a novel lipophilic 5-FU carbonate [XL-01, (5-fluoro-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl) methyl tetradecyl carbonate] was designed, synthesized, and encapsulated into liposome (LipoXL-01) by a thin-film dispersion method through formulation screening and optimization. LipoXL-01 was characterized by a particle size of around 100 nm, polydispersity index of 0.200, ζ-potential value of -41 mV, encapsulation efficiency of 93.9%, and drug-loading efficiency of 11.6%. The cellular uptake of LipoXL-01 was increased in a concentration-dependent manner on HCT15 cells. LipoXL-01 could enhance the induction of cell apoptosis and the inhibition of cell migration and arrest the ability of the cell cycle at the S-phase on HCT15 cells better than 5-FU. Additionally, LipoXL-01 exhibited a slow drug release profile with a cumulative release rate of 12% in 8 h. The results of pharmacokinetic and biodistribution studies revealed that LipoXL-01 had a long plasma half-life (7.21 h) and a high tumor accumulation (733 nmol/g at 8 h). The in vivo antitumor effect study also showed that LipoXL-01 had more potent efficacy than 5-FU (65 vs 48% of the tumor-inhibition rate). Simultaneously, negligible systemic toxicity was observed via analyzing the body weight as well as hematological and pathological parameters in the tested mice. The current study suggested that LipoXL-01 might be a promising nanocandidate for chemotherapy of colorectal cancer.

The Role of Ferroptosis in the Treatment and Drug Resistance of Hepatocellular Carcinoma

Cell death is a fundamental feature of multicellular organisms’ development and a key driver of degenerative diseases. Ferroptosis is a new regulatory cell death mediated by iron-dependent lipid peroxidation, which is different from apoptosis and necrosis in morphology, pathophysiology and mechanism. Recent studies have found that ferroptosis is involved in the development of many diseases including hepatocellular carcinoma (HCC). As further research progresses, specific mechanisms of ferroptosis in HCC are being revealed. In this review, we summarize these recent advances about the treatment of drug-resistance in HCC and the latest ferroptosis-related treatment for HCC.

Radio-sensitivity enhancement in HT29 cells through magnetic hyperthermia in combination with targeted nano-carrier of 5-Flourouracil

Normal tissue complication and development of radioresistance in cancer cells are known as the main challenges of ionizing radiation treatment. In the current study, we intended to induce selective radiosensitization in HT29 cancer cells by developing folic acid modified magnetic triblock copolymer nanoparticles as carrier of 5-Flourouracil (5-FU) which was further used in combination with hyperthermia. The aforementioned nanoparticles were synthesized and characterized by differential scanning calorimetric analysis (DSC), UV-visible spectroscopy, dynamic light scattering (DLS), zeta sizer, and transmission electron microscopy (TEM). These nanoparticles were also assessed to determine drug loading capacity (DLC %) and drug release profile. The cytotoxicity of nanoparticles was evaluated on two different cell lines: HUVEC and HT29. Furthermore, radiosensitivity induction of the nanoparticles with and without exposure of alternative magnetic field was investigated. MTT-based cytotoxicity assay demonstrated that the therapeutic ratio was enhanced in response to using 5-FU-loaded nanoparticles as compared to 5-FU. Various characterizations including gene expression study, measurement of reactive oxygen species (ROS) generation, Annexin V/PI staining, and clonogenic assay revealed that ionizing radiation in combination with hyperthermia in the presence of the synthesized nanoparticles led to maximal anti-cancer effects as compared to other single (P < 0.001) and combined treatments (P < 0.01). Our results suggested that combined treatment based on using folic acid modified magnetic copolymer nanoparticle as carrier of 5-FU accompanied with hyperthermia could be proposed as an efficient approach to enhance radiation effects in cancer cells.

Influence of Liver Intoxication by Carbon Tetrachloride or D-Galactosamine on Absorption of Fluorescein Isothiocyanate-Dextran-10 and Other Marker Compounds with Different Molecular Weights from the Rat Liver Surface

We examined the influence of liver disease on the absorption from the liver surface of fluorescein isothiocyanate (FITC)-dextran 10 (FD-10, MW: 11000) and several marker compounds with different molecular weights. The purpose of this study was to determine the feasibility of liver surface application of macromolecular compounds in the disease state. We used male Wistar rats treated with carbon tetrachloride (CCl₄) or D-galactosamine (GAL). FD-10 and other marker compounds were applied to the liver surface using a cylindrical diffusion cell in liver-intoxicated rats. The blood, bile, urine, and the remaining solution in the diffusion cell were collected for assay. FD-10 was absorbed by first-order kinetics from the liver surface in the liver-intoxicated rat models. The calculated rate constant k_a values in the normal, CCl₄ and GAL groups were 0.000965, 0.00125 and 0.00104 min^-1, respectively. Increased absorption of FITC-dextrans in the liver-intoxicated rats was observed. In both CCl₄ and GAL groups, an inverse relationship was observed between the molecular weight and k_a from the rat liver surface of the marker compounds. The limits of the molecular weight absorbed from the liver surface were extrapolated to be 71200, 135000, and 105000 in the normal, CCl₄, and GAL groups, respectively. In conclusion, increased absorbability from the rat liver surface indicates that liver surface application for liver targeting of macromolecules in the diseased state is indeed feasible. Therefore, our findings can support further research on liver surface application of drugs under liver disease.

Evaluation of Polymer Nanoformulations in Hepatoma Therapy by Established Rodent Models

Hepatoma is one of the most severe malignancies usually with poor prognosis, and many patients are insensitive to the existing therapeutic agents, including the drugs for chemotherapy and molecular targeted therapy. Currently, researchers are committed to developing the advanced formulations with controlled drug delivery to improve the efficacy of hepatoma therapy. Numerous inoculated, induced, and genetically engineered hepatoma rodent models are now available for formulation screening. However, animal models of hepatoma cannot accurately represent human hepatoma in terms of histological characteristics, metastatic pathways, and post-treatment responses. Therefore, advanced animal hepatoma models with comparable pathogenesis and pathological features are in urgent need in the further studies. Moreover, the development of nanomedicines has renewed hope for chemotherapy and molecular targeted therapy of advanced hepatoma. As one kind of advanced formulations, the polymer-based nanoformulated drugs have many advantages over the traditional ones, such as improved tumor selectivity and treatment efficacy, and reduced systemic side effects. In this article, the construction of rodent hepatoma model and much information about the current development of polymer nanomedicines were reviewed in order to provide a basis for the development of advanced formulations with clinical therapeutic potential for hepatoma.

An active molecule from Pulsatilla chinensis, Pulsatilla saponin A, induces apoptosis and inhibits tumor growth of human colon cancer cells without or with 5-FU

Colon cancer is one of the common types of digestive malignancy. The efficacy of the first-line chemotherapy drug for colon cancer, fluorouracil (5-FU), remains limited in clinical settings due to poor efficacy and significant side effects. In the present study, the anticancer activity of an active compound from Pulsatilla chinensis extracts, Pulsatilla saponin A (PsA), was isolated and examined in vitro and in vivo. It was demonstrated that PsA significantly inhibited the growth of human colon cancer HT-29 cells. This inhibitory activity was also observed when the compound was tested in a colon cancer xenograft mouse model. Additionally, the synergic antitumor effects of PsA and 5-FU on colon cancer cells were observed. Using annexin V and terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling assays, it was demonstrated that levels of apoptosis induction in HT-29 cells treated with PsA or 5-FU were significantly increased compared with the untreated control cells (P<0.05). Western blot analyses were then performed, and the results revealed an increase in tumor protein 53 and cleaved caspase 9, and a decrease in B-cell lymphoma 2 protein expressions in PsA and PsA + 5-FU treated colon cancer cells compared with the vehicle-treated (PBS) cells. In summary, PsA exhibited anticancer activity in human colon cancer cells in vitro and in vivo, in isolation and synergistically with 5-FU, through apoptosis induction.

Melatonin synergizes the chemotherapeutic effect of 5-fluorouracil in colon cancer by suppressing PI3K/AKT and NF-κB/iNOS signaling pathways

5-Fluorouracil (5-FU) is one of the most commonly used chemotherapeutic agents in colon cancer treatment, but has a narrow therapeutic index limited by its toxicity. Melatonin exerts antitumor activity in various cancers, but it has never been combined with 5-FU as an anticolon cancer treatment to improve the chemotherapeutic effect of 5-FU. In this study, we assessed such combinational use in colon cancer and investigated whether melatonin could synergize the antitumor effect of 5-FU. We found that melatonin significantly enhanced the 5-FU-mediated inhibition of cell proliferation, colony formation, cell migration and invasion in colon cancer cells. We also found that melatonin synergized with 5-FU to promote the activation of the caspase/PARP-dependent apoptosis pathway and induce cell cycle arrest. Further mechanism study demonstrated that melatonin synergized the antitumor effect of 5-FU by targeting the PI3K/AKT and NF-κB/inducible nitric oxide synthase (iNOS) signaling. Melatonin in combination with 5-FU markedly suppressed the phosphorylation of PI3K, AKT, IKKα, IκBα, and p65 proteins, promoted the translocation of NF-κB p50/p65 from the nuclei to cytoplasm, abrogated their binding to the iNOS promoter, and thereby enhanced the inhibition of iNOS signaling. In addition, pretreatment with a PI3K- or iNOS-specific inhibitor synergized the antitumor effects of 5-FU and melatonin. Finally, we verified in a xenograft mouse model that melatonin and 5-FU exerted synergistic antitumor effect by inhibiting the AKT and iNOS signaling pathways. Collectively, our study demonstrated that melatonin synergized the chemotherapeutic effect of 5-FU in colon cancer through simultaneous suppression of multiple signaling pathways.

PUMA mediates the combinational therapy of 5-FU and NVP-BEZ235 in colon cancer

Colon cancer is the third most common cancer in humans which has a high mortality rate, and 5-Fluorouracil (5-FU) is one of the most widely used drugs in colon cancer therapy. However, acquired chemoresistance is becoming the major challenges for patients, and the molecular mechanism underlying the development of 5-FU resistance is still poorly understood. In this study, a newly designed therapy in combination with 5-FU and NVP-BEZ235 in colon cancer cells (HCT-116 and RKO) was established, to investigate the mechanism of 5-FU resistance and optimize drug therapy to improve outcome for patients. Our results show 5-FU induced cell apoptosis through p53/PUMA pathway, with aberrant Akt activation, which may well explain the mechanism of 5-FU resistance. NVP-BEZ235 effectively up-regulated PUMA expression, mainly through inactivation of PI3K/Akt and activation of FOXO3a, leading to cell apoptosis even in the p53^−/− HCT-116 cells. Combination treatment of 5-FU and NVP-BEZ235 further increased cell apoptosis in a PUMA/Bax dependent manner. Moreover, significantly enhanced anti-tumor effects were observed in combination treatment in vivo. Together, these results demonstrated that the combination treatment of 5-FU and NVP-BEZ235 caused PUMA-dependent tumor suppression both in vitro and in vivo, which may promise a more effective strategy for colon cancer therapy.

Effect of Metabolic Inhibitors on the Hepatic Disposition of 5-Fluorouracil after Application to the Rat Liver Surface

We evaluated the effects of 5-fluorouracil (5-FU) metabolic inhibitors, gimeracil or uridine, on the hepatic disposition of 5-FU after application to the liver surface in rats, aiming to enhance the availability of 5-FU in the liver. 5-FU solution with or without metabolic inhibitors was applied to the rat liver surface using a cylindrical diffusion cell. The liver, blood and the remaining solution in the diffusion cell were collected at specified times, and assayed for 5-FU content. 5-FU absorption properties were not altered by addition of gimeracil and uridine. The 5-FU concentration in the diffusion cell attachment site of the rat liver (site 1) at 0.1-0.4 M ratios of gimeracil to 5-FU was significantly higher than that of the control. On the contrary, the addition of uridine did not increase the 5-FU concentration at site 1. At a 0.1 M ratio of gimeracil to 5-FU, the maximum 5-FU plasma concentration was the lowest, and the area under the 5-FU concentration-time curve at site 1 was 3.4 times greater than that of the control. We demonstrated that applying 5-FU with gimeracil to the rat liver surface could increase the availability of 5-FU in the liver.

Chemotherapeutic agents for the treatment of hepatocellular carcinoma: efficacy and mode of action

Hepatocellular carcinoma (HCC) is a dreaded malignancy that every year causes half a million deaths worldwide. Being an aggressive cancer, its incidence exceeds 700,000 new cases per year worldwide with a median survival of 6-8 months. Despite advances in prognosis and early detection, effective HCC chemoprevention or treatment strategies are still lacking, therefore its dismal survival rate remains largely unchanged. This review will characterize currently available chemotherapeutic drugs used in the treatment of HCC. The respective mode(s) of action, side effects and recommendations will be also described for each drug.

Increase of cyclooxygenase-2 inhibition with celecoxib combined with 5-FU enhances tumor cell apoptosis and antitumor efficacy in a subcutaneous implantation tumor model of human colon cancer

Background

The purpose of this study was to investigate the anti-tumor effect and explore the mechanisms of celecoxib (a selective cyclooxygenase-2 inhibitor) combined with 5-fluorouracil (5-FU) on the treatment of human colorectal cancer in a BALB/C nude mouse subcutaneous xenograft model.

Methods

Effects of celecoxib combined with 5-FU on the proliferation of xenograft carcinoma induced by HT-29 were investigated. The apoptotic cells were detected by electron microscope and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay. Immunohistochemistry and Western blot were used to estimate the expression of cytochrome C, caspase-3 and caspase-9.

Results

Compared with the control group, treatment groups showed significant inhibition of tumor growth. More apoptotic cells existed after treatment with celecoxib combined with 5-FU. Cytochrome C, caspase-3 and caspase-9 were increased in treated groups, and more obviously in the drug combination group. Cyclooxygenase-2 (COX-2) were decreased after treatment with celecoxib only or combined with 5-FU. And the combined group showed a greater decrease.

Conclusions

Celecoxib combined with 5-FU could inhibit the growth of tumors in vivo by inducing apoptosis and activation of the cytochrome C dependency apoptosis signal pathway. A decrease of COX-2 and an increase of cytochrome C, caspase-3 and caspase-9 may be involved in this process.

5-Fluorouracil nanoparticles inhibit hepatocellular carcinoma via activation of the p53 pathway in the orthotopic transplant mouse model

Biodegradable polymer nanoparticle drug delivery systems provide targeted drug delivery, improved pharmacokinetic and biodistribution, enhanced drug stability and fewer side effects. These drug delivery systems are widely used for delivering cytotoxic agents. In the present study, we synthesized GC/5-FU nanoparticles by combining galactosylated chitosan (GC) material with 5-FU, and tested its effect on liver cancer in vitro and in vivo. The in vitro anti-cancer effects of this sustained release system were both dose- and time-dependent, and demonstrated higher cytotoxicity against hepatic cancer cells than against other cell types. The distribution of GC/5-FU in vivo revealed the greatest accumulation in hepatic cancer tissues. GC/5-FU significantly inhibited tumor growth in an orthotropic liver cancer mouse model, resulting in a significant reduction in tumor weight and increased survival time in comparison to 5-FU alone. Flow cytometry and TUNEL assays in hepatic cancer cells showed that GC/5-FU was associated with higher rates of G0-G1 arrest and apoptosis than 5-FU. Analysis of apoptosis pathways indicated that GC/5-FU upregulates p53 expression at both protein and mRNA levels. This in turn lowers Bcl-2/Bax expression resulting in mitochondrial release of cytochrome C into the cytosol with subsequent caspase-3 activation. Upregulation of caspase-3 expression decreased poly ADP-ribose polymerase 1 (PARP-1) at mRNA and protein levels, further promoting apoptosis. These findings indicate that sustained release of GC/5-FU nanoparticles are more effective at targeting hepatic cancer cells than 5-FU monotherapy in the mouse orthotropic liver cancer mouse model.

Relationship between lipophilicity and absorption from the liver surface of paraben derivatives and antipyrine in rats

OBJECTIVES

The importance of drug lipophilicity on absorption from the liver surface was examined in rats using paraben derivatives, antipyrine, Sudan III, and Sudan blue.

METHODS

The log partition coefficient (PC) of n-octanol/water ranged from -1.39 to 4.62. The compounds were applied to the rat liver surface using a cylindrical diffusion cell (i.d. 9 mm).

KEY FINDINGS

The rate of absorption at 15 min was calculated to be 13.9% for paraben, much lower than that for its derivatives methylparaben, propylparaben and butylparaben (∼ 80%). The obtained first-order absorption rate constant (k(a) ) of paraben, methylparaben, propylparaben and antipyrine increased according to lipophilicity. Further lipophilicity resulted in a fall in k(a) , implying the importance of affinity for lipids and water in absorption from the liver surface. Thus, a compound with a log PC of around 2.5 is considered to have maximum absorbability from the rat liver surface. A good relationship (r(2) = 0.97) was recognized between the log k(a) and log reciprocal value with the square root of molecular weight of the compounds with a log PC below 2.5.

CONCLUSIONS

The rate of absorption of a drug from the liver surface could be estimated from physicochemical properties such as lipophilicity and molecular weight.

[Development of drug delivery system by utilizing absorption from liver surface and its application]

Because it is difficult to achieve local drug activity following administration by the conventional intravenous and oral routes, I sought to develop a new route of administration utilizing drug absorption from the liver surface in order to target that organ. Although direct application to the liver surface should yield local drug distribution, drug absorption from the liver surface has not been reported in the literature. Therefore, we analyzed, as a model, the efficiency of absorption of several organic anions and dextrans of various molecular weights following application to the rat liver surface in vivo using a cylindrical diffusion cell. Each compound appeared gradually in the plasma, followed by excretion into the bile and/or urine, indicating the possibility of drug absorption from the liver surface. The absorption process from the liver surface may not involve a specific transport system because dose and transport inhibitors had no detectable effect. In addition, molecular weight was found to be a determinant of absorption through the liver surface. The efficiency of targeting desired region in the liver was enhanced considerably by application to the liver surface, compared to intravenous administration. Moreover, I have obtained several promising results from the application of this new drug delivery system to anticancer drugs and gene therapy. On the other hand, I have also clarified the characteristics of drug absorption from the surfaces of the kidney, stomach, cecum and small intestine, and plan to apply the physiological findings to other fields.