An alternative hybrid lipid nanosystem combining cytotoxic and magnetic properties as a tool to potentiate antitumor effect of 5-fluorouracil

AIMS

Colorectal cancer is the third most frequent type of cancer and the second leading cause of cancer-related deaths worldwide. The majority of cases are diagnosed at a later stage, leading to the need for more aggressive treatments such as chemotherapy. 5-Fluorouracil (5-FU), known for its high cytotoxic properties has emerged as a chemotherapeutic agent. However, it presents several drawbacks such as lack of specificity and short half-life. To reduce these drawbacks, several strategies have been designed namely chemical modification or association to drug delivery systems.

MATERIALS AND METHODS

Current research was focused on the design, physicochemical characterization and in vitro evaluation of a lipid-based system loaded with 5-FU. Furthermore, aiming to maximize preferential targeting and release at tumour sites, a hybrid lipid-based system, combining both therapeutic and magnetic properties was developed and validated. For this purpose, liposomes co-loaded with 5-FU and iron oxide (II, III) nanoparticles were accomplished.

KEY FINDINGS

The characterization of the developed nanoformulation was performed in terms of incorporation parameters, mean size and surface charge. In vitro studies assessed in a murine colon cancer cell line confirmed that 5-FU antiproliferative activity was preserved after incorporation in liposomes. In same model, iron oxide (II, III) nanoparticles did not exhibit cytotoxic properties. Additionally, the presence of these nanoparticles was shown to confer magnetic properties to the liposomes, allowing them to respond to external magnetic fields.

SIGNIFICANCE

Overall, a lipid nanosystem loading a chemotherapeutic agent displaying magnetic characteristics was successfully designed and physicochemically characterized, for further in vivo applications.

Colorectal cancer mouse metastasis model combining bioluminescent and micro-computed tomography imaging for monitoring the effects of 5-fluorouracil treatment

Background

Colorectal cancer (CRC) is the fifth most fatal cancer with a low probability of surgery and limited treatment options, especially in metastatic CRC. In this study, we investigated whether a mouse model of metastatic CRC mimicked tumor progression and evaluated the effect of 5-fluorouracil (5-FU) treatment.

Methods

The CT26 mouse derived CRC cancer cell line was inoculated into mice, and the tumor bearing mice were divided into two groups: the experimental group and the control group. Micro-computed tomography (CT) and in vivo fluorescence were used to monitor the progression of metastatic CRC. A lung metastasis mouse model was employed to determine the effects of 5-FU on metastasis.

Results

Bioluminescence imaging (BLI) and computed tomography (CT), as non-invasive methods, can continuously monitor the growth of tumors in vivo. Thus, imaging techniques can be used to qualitatively and quantitatively evaluate tumor growth indicators. 5-FU injected intravenously reduced the viability of metastatic CRC cells and resulted in prolonged survival compared to the control group. Moreover, the 5-FU-treated group had significantly reduced fluorescence of the CT26 cells in the lung. The results observed by BLI and CT are consistent with the tissue morphology and structure presented in pathological examination.

Conclusions

In summary, a successful mouse model of CRC metastasis for clinical application has been established.

Preclinical Synergistic Combination Therapy of Lurbinectedin with Irinotecan and 5-Fluorouracil in Pancreatic Cancer

Pancreatic cancer is a devastating disease with a poor prognosis. Novel chemotherapeutics in pancreatic cancer have shown limited success, illustrating the urgent need for new treatments. Lurbinectedin (PM01183; LY-01017) received FDA approval in 2020 for metastatic small cell lung cancer on or after platinum-based chemotherapy and is currently undergoing clinical trials in a variety of tumor types. Lurbinectedin stalls and degrades RNA Polymerase II and introduces breaks in DNA, causing subsequent apoptosis. We now demonstrate lurbinectedin's highly efficient killing of human-derived pancreatic tumor cell lines PANC-1, BxPC-3, and HPAF-II as a single agent. We further demonstrate that a combination of lurbinectedin and irinotecan, a topoisomerase I inhibitor with FDA approval for advanced pancreatic cancer, results in the synergistic killing of pancreatic tumor cells. Western blot analysis of combination therapy indicates an upregulation of γH2AX, a DNA damage marker, and the Chk1/ATR pathway, which is involved in replicative stress and DNA damage response. We further demonstrate that the triple combination between lurbinectedin, irinotecan, and 5-fluorouracil (5-FU) results in a highly efficient killing of tumor cells. Our results are developing insights regarding molecular mechanisms underlying the therapeutic efficacy of a novel combination drug treatment for pancreatic cancer.

THOC2 expression and its impact on 5-fluorouracil resistance in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with poor prognosis and limited treatment options. While 5-fluorouracil (5-FU) has not been widely employed in GBM therapy, emerging research indicates its potential for effectiveness when combined with advanced drug delivery systems to improve its transport to brain tumors. This study aims to investigate the role of THOC2 expression in 5-FU resistance in GBM cell lines. We evaluated diverse GBM cell lines and primary glioma cells for 5-FU sensitivity, cell doubling times, and gene expression. We observed a significant correlation between THOC2 expression and 5-FU resistance. To further investigate this correlation, we selected five GBM cell lines and developed 5-FU resistant GBM cells, including T98FR cells, through long-term 5-FU treatment. In 5-FU challenged cells, THOC2 expression was upregulated, with the highest increase in T98FR cells. THOC2 knockdown in T98FR cells reduced 5-FU IC50 values, confirming its role in 5-FU resistance. In a mouse xenograft model, THOC2 knockdown attenuated tumor growth and extended survival duration after 5-FU treatment. RNA sequencing identified differentially expressed genes and alternative splicing variants in T98FR/shTHOC2 cells. THOC2 knockdown altered Bcl-x splicing, increasing pro-apoptotic Bcl-xS expression, and impaired cell adhesion and migration by reducing L1CAM expression. These results suggest that THOC2 plays a crucial role in 5-FU resistance in GBM and that targeting THOC2 expression could be a potential therapeutic strategy for improving the efficacy of 5-FU-based combination therapies in GBM patients.

WDR76 regulates 5-fluorouracil sensitivity in colon cancer via HRAS

BACKGROUND

WD repeat domain 76 (WDR76) has been reported in multiple tumors, while without relation to chemotherapy resistance. 5-fluorouracil (5-FU) is widely adopted in treating colon cancer. However, the resistance of WDR76 and 5-FU in colon cancer remains unclear.

METHODS

Limma package in R software was employed to analyze the differentially expressed genes. Western blot or quantitative real-time PCR (qRT-PCR) were run to assessed the gene expression. The cytotoxic effect was determined according to cell viability assay, colony formation assay in vitro. Cell apoptosis was assayed using flow cytometry. GSEA analysis was performed to identify pathways related to the target gene. Xenografted mice model was employed to evaluate the tumor growth.

RESULTS

Bioinformatic analysis revealed the higher expression of WDR76 in 5-FU sensitive colon cancer cells compared to resistant colon cancer cells, accompanied by the decreased mRNA expression of WDR76 in 5-FU resistant colon cancer cells. The overexpressed WDR76 resulted in the apoptosis and the downregulated colony numbers in 5-FU resistant colon cancer cells, leading to the elevated sensitivity of 5-FU. Meanwhile, knockdown of WDR76 enhances the resistance of 5-FU in colon cancer both in vitro and vivo, which was reversed by a specific inhibitor of HRAS, Kobe006. An important molecular mechanism of 5-FU resistance lies the degradation of HRAS induced by WDR76.

CONCLUSION

Our findings demonstrated a role of WDR76 as a promising target for reversing the resistance of colon cancer to 5-FU.

The Management of Ocular Surface Squamous Neoplasia (OSSN)

The rise of primary topical monotherapy with chemotherapeutic drugs and immunomodulatory agents represents an increasing recognition of the medical management of ocular surface squamous neoplasia (OSSN), which may replace surgery as the standard of care in the future. Currently, there is no consensus regarding the best way to manage OSSN with no existing guidelines to date. This paper seeks to evaluate evidence surrounding available treatment modalities and proposes an approach to management. The approach will guide ophthalmologists in selecting the most appropriate treatment regime based on patient and disease factors to minimize treatment related morbidity and improve OSSN control. Further work can be done to validate this algorithm and to develop formal guidelines to direct the management of OSSN.

Functional Phosphoproteomics in Cancer Chemoresistance Using CRISPR-Mediated Base Editors

Selective inhibition of targeted protein kinases is an effective therapeutic approach for treatment of human malignancies, which interferes phosphorylation of cellular substrates. However, a drug-imposed selection creates pressures for tumor cells to acquire chemoresistance-conferring mutations or activating alternative pathways, which can bypass the inhibitory effects of kinase inhibitors. Thus, identifying downstream phospho-substrates conferring drug resistance is of great importance for developing poly-pharmacological and targeted therapies. To identify functional phosphorylation sites involved in 5-fluorouracil (5-FU) resistance during its treatment of colorectal cancer cells, CRISPR-mediated cytosine base editor (CBE) and adenine base editor (ABE) are utilized for functional screens by mutating phosphorylated amino acids with two libraries specifically targeting 7779 and 10 149 phosphorylation sites. Among the top enriched gRNAs-induced gain-of-function mutants, the target genes are involved in cell cycle and post-translational covalent modifications. Moreover, several substrates of RSK2 and PAK4 kinases are discovered as main effectors in responding to 5-FU chemotherapy, and combinational treatment of colorectal cancer cells with 5-FU and RSK2 inhibitor or PAK4 inhibitor can largely inhibit cell growth and enhance cell apoptosis through a RSK2/TP53BP1/γ-H2AX phosphorylation signaling axis. It is proposed that this screen approach can be used for functional phosphoproteomics in chemotherapy of various human diseases.

5-Fluorouracil in primary, impending recurrent and recurrent pterygium: Systematic review of the efficacy and safety of a surgical adjuvant and intralesional antimetabolite

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

Mir-675-5p supports hypoxia-induced drug resistance in colorectal cancer cells

Background

The uncontrolled proliferation of cancer cells determines hypoxic conditions within the neoplastic mass with consequent activation of specific molecular pathways that allow cells to survive despite oxygen deprivation. The same molecular pathways are often the cause of chemoresistance. This study aims to investigate the role of the hypoxia-induced miR-675-5p in 5-Fluorouracil (5-FU) resistance on colorectal cancer (CRC) cells.

Methods

CRC cell lines were treated with 5-Fu and incubated in normoxic or hypoxic conditions; cell viability has been evaluated by MTT assay. MiR-675-5p levels were analysed by RT-PCR and loss and gain expression of the miRNA has been obtained by the transfection of miRNA antagomir or miRNA mimic. Total protein expression of different apoptotic markers was analysed through western blot assay. MirWalk 2.0 database search engine was used to investigate the putative targets of the miR-675-5p involved in the apoptotic process. Finally, the luciferase assay was done to confirm Caspase-3 as a direct target of the miR-675-5p.

Results

Our data demonstrated that hypoxia-induced miR-675-5p counteracts the apoptotic signal induced by 5-FU, thus taking part in the drug resistance response. We showed that the apoptotic markers, cleaved PARP and cleaved caspase-3, increased combining miR-675-5p inhibition with 5-FU treatment. Moreover, we identified pro-caspase-3 among the targets of the miR-675-5p.

Conclusion

Our data demonstrate that the inhibition of hypoxia-induced miR-675-5p combined with 5-FU treatment can enhances drug efficacy in both prolonged hypoxia and normoxia, indicating a possible strategy to partially overcome chemoresistance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09666-2.

Affibody-conjugated 5-fluorouracil prodrug system preferentially targets and inhibits HER2-expressing cancer cells

Overexpression of HER2 is associated with cancer phenotypes, such as proliferation, survival, metastasis and angiogenesis, and has been validated as a therapeutic target. However, only a portion of patients benefited from anti-HER2 treatments, and many would develop resistance. A more effective HER2 targeted therapeutics is needed. Here, we adopted a prodrug system that uses 5-fluorocytosine (5-FC) and a HER2-targeting scaffold protein, Z_HER2:2891, fused with yeast cytosine deaminase (Fcy) to target HER2-overexpressing cancer cells and to convert 5-FC to a significantly more toxic chemotherapeutic, 5-fluorouracil (5-FU). We cloned the coding gene of Z_HER2:2891 and fused with those of ABD (albumin-binding domain) and Fcy. The purified Z_HER2:2891-ABD-Fcy fusion protein specifically binds to HER2 with a Kd value of 1.6 nM Z_HER2:2891-ABD-Fcy binds to MDA-MB-468, SKOV-3, BT474, and MC38-HER2 cells, which overexpress HER2, whereas with a lower affinity to HER2 non-expresser, MC38. Correspondingly, the viability of HER2-expressing cells was suppressed by relative low concentrations of Z_HER2:2891-ABD-Fcy in the presence of 5-FC, and the IC₅₀ values of Z_HER2:2891-ABD-Fcy for HER2 high-expresser cells were approximately 10-1000 fold lower than those of non-HER2-targeting Fcy, and ABD-Fcy. This novel prodrug system, Z_HER2:2891-ABD-Fcy/5-FC, might become a promising addition to the existing class of therapeutics specifically target HER2-expressing cancers.

An Oral Fluorouracil Prodrug, Capecitabine, Mitigates a Gram-Positive Systemic Infection in Mice

New classes of antibiotics are needed to fight bacterial infections, and repurposing existing drugs as antibiotics may enable rapid deployment of new treatments. Screens for antibacterials have been traditionally performed in standard laboratory media, but bacterial pathogens experience very different environmental conditions during infection, including nutrient limitation. To introduce the next generation of researchers to modern drug discovery methods, we developed a course-based undergraduate research experience (CURE) in which undergraduate students screened a library of FDA-approved drugs for their ability, in a nutrient-poor medium, to prevent the growth of the human Gram-negative bacterial pathogen Salmonella enterica serovar Typhimurium. The nine drugs identified all disrupt DNA metabolism in bacteria and eukaryotes. One of the hit compounds, capecitabine, is a well-tolerated oncology drug that is administered orally, a preferred treatment route. We demonstrated that capecitabine is more effective at inhibiting S. Typhimurium growth in nutrient-limited than in standard rich microbiological broth, an explanation for why the antibiotic activity of this compound has not been previously recognized. Capecitabine is enzymatically converted to the active pyrimidine analogue, fluorouracil (5-FU), and Gram-positive bacteria, including Staphylococcus aureus, are significantly more sensitive to 5-FU than Gram-negative bacteria. We therefore tested capecitabine for efficacy in a murine model of S. aureus peritonitis. Oral capecitabine administration reduced the colonization of tissues and increased animal survival in a dose-responsive manner. Since capecitabine is inexpensive, orally available, and relatively safe, it may have utility for treatment of intractable Gram-positive bacterial infections. IMPORTANCE As bacterial infections become increasingly insensitive to antibiotics, whether established, off-patent drugs could treat infections becomes an important question. At the same time, basic research has revealed that during infection, mammals starve pathogens for nutrients and, in response, bacteria dramatically alter their biology. Therefore, it may be fruitful to search for drugs that could be repurposed as antibiotics using bacteria grown with limited nutrients. This approach, executed with undergraduate student researchers, identified nine drugs known to interfere with the production and/or function of DNA. We further explored one of these drugs, capecitabine, a well-tolerated human oncology drug. Oral administration of capecitabine reduced infection with the human pathogen Staphylococcus aureus and increased survival in mice. These data suggest that capecitabine has potential as a therapy for patients with otherwise untreatable bacterial infections.

Demethylzeylasteral Exerts Antitumor Effects via Disruptive Autophagic Flux and Apoptotic Cell Death in Human Colorectal Cancer Cells and Increases Cell Chemosensitivity to 5-Fluorouracil

BACKGROUND

Demethylzeylasteral (ZST93), a pharmacologically active triterpenoid monomer extracted from Tripterygium wilfordii Hook F (TWHF), has been reported to exert antineoplastic effects in several cancer cell types. However, the anti-tumour effects of ZST93 in human colorectal cancer (CRC) cells are unknown.

OBJECTIVE

The aim of the present study was to evaluate the antitumor effects of ZST93 on cell cycle arrest, disruptive autophagic flux, apoptotic cell death, and enhanced chemosensitivity to 5-FU in humans CRC cells.

METHODS

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay, colony formation assay, flow cytometry, immunoblotting, immunofluorescence, 5-ethynyl-20-deoxyuridine (EdU) incorporation assay, and autophagy analysis were used to evaluate the effects of ZST93 on cell viability, cell cycle progression, apoptosis and autophagy in two human CRC cell lines. Moreover, ZST93's combined anti-tumour effects with 5-fluorouracil (5-FU) were evaluated.

RESULTS

ZST93 inhibited CRC cell proliferation and growth. It was responsible for blocked cell cycle transition by arresting CRC cells in the G0/G1 phase via down-regulation of CDK4, CDK6, Cyclin D1, and c-MYC. Moreover, ZST93 induced suppressive autophagic flux and caspase-3-dependent cell death, which were further strengthened by the blocking of the autophagy process using chloroquine (CQ). Moreover, ZST93 enhanced CRC cells' chemosensitivity to 5-FU via modulation of autophagy and apoptosis.

CONCLUSION

ZST93 exerts anti-tumour effects via disruptive autophagic flux and apoptotic cell death in human CRC cells and increases cell chemosensitivity to 5-FU. These results provide insights into the utilisation of ZST93 as an adjuvant or direct autophagy inhibitor and suggest ZST93 as a novel therapeutic strategy for treating CRC.

Tumor budding as a predictive marker for 5-fluorouracil response in adjuvant-treated stage III colorectal cancer

BACKGROUND

Tumor budding (TB) has been described as an adverse prognostic marker for operable colorectal cancer (CRC); however, a limited number of studies have demonstrated the prognostic significance of TB in patients with drug therapy. This study was conducted to determine the predictive power of TB in stage III CRC patients who received adjuvant chemotherapy.

METHODS

We retrospectively collected clinicopathological data including TB of 237 stage III colorectal cancer patients at Hiroshima University Hospital between July 1, 2006 and June 31, 2019. Differential disease-free survival (DFS) was investigated according to TB status.

RESULTS

This study included 237 patients with a median age of 67 years, comprising patients who underwent surgery alone (n = 65), 5-fluorouracil (5-FU) monotherapy (n = 129), and oxaliplatin-based chemotherapy (n = 43). Overall, 81 patients developed disease recurrence, and 33 patients died of cancer-related causes. The TB status was categorized into two groups: 99 with low budding (< 5 buds) and 138 with high budding (≥ 5 buds). Overall, the low budding cases demonstrated significantly better DFS. In the 5-FU monotherapy group, low-risk patients (T1, T2, or T3 and N1) with low budding showed a remarkably higher 3-year DFS (91%) compared to high budding (55%).

CONCLUSION

Our results indicate that TB could play a subsidiary role in selecting patients who could maintain a favorable prognosis with 5-FU monotherapy in stage III CRC.

Effect of 5-fluorouracil on branched-chain α-keto acid dehydrogenase (BCKDH) complex in rat's heart

Undisturbed branched-chain amino acids (BCAA) catabolism is necessary for normal heart function. The key enzyme in BCAA catabolism is a multienzyme branched-chain α-keto acid dehydro- genase complex (BCKDH). BCKDH activity is regulated mainly by reversible dephosphorylation (activa- tion)/phosphorylation (inactivation) cycle catalyzed by regulatory enzymes, a specific phosphatase (PPM1K) and kinase (BDK). 5-fluorouracil (5-FU) is widely used in the treatment of different types of cancer. 5-FU has the potential to cause a wide spectrum of cardiotoxicity, ranging from asymptomatic electrocardiographic changes to cardiomyopathy and subsequent cardiac failure. We hypothesize that 5-FU modifies BCKDH activity and affects cardiac muscle metabolism. The current study was aimed at the investigation of the in vivo effect of 5-FU on BCKDH activity and mRNA levels for E1, PPM1K and BDK. Wistar male rats were administered with 4 doses of 5-FU, 150 mg/kg b.wt. each (study group) or 0.3% methylcellulose (control group). BCKDH activity was assayed spectrophotometrically. The mRNA levels were quantified by real-time PCR. 5-FU treatment caused an increase in BCKDH activity that appears to result mainly from increased dephosphorylation of the complex and is associated with an increase of PPM1K mRNA level and reduction of BDK and E1 mRNA levels. It is conceivable that 5-FU stimulation of BCKDH is an adaptive reaction with the purpose of enhancing the BCAA catabolism and protecting from toxic effect caused by excessive accumulation of these amino acids in heart.

Elucidating the Drug Release from Metal-Organic Framework Nanocomposites via In Situ Synchrotron Microspectroscopy and Theoretical Modeling

Nanocomposites comprising metal-organic frameworks (MOFs) embedded in a polymeric matrix are promising carriers for drug delivery applications. While understanding the chemical and physical transformations of MOFs during the release of confined drug molecules is challenging, this is central to devising better ways for controlled release of therapeutic agents. Herein, we demonstrate the efficacy of synchrotron microspectroscopy to track the in situ release of 5-fluorouracil (5-FU) anticancer drug molecules from a drug@MOF/polymer composite (5-FU@HKUST-1/polyurethane). Using experimental time-resolved infrared spectra jointly with newly developed density functional theory calculations, we reveal the detailed dynamics of vibrational motions underpinning the dissociation of 5-FU bound to the framework of HKUST-1 upon water exposure. We discover that HKUST-1 creates hydrophilic channels within the hydrophobic polyurethane matrix hence helping to tune drug release rate. The synergy between a hydrophilic MOF with a hydrophobic polymer can be harnessed to engineer a tunable nanocomposite that alleviates the unwanted burst effect commonly encountered in drug delivery.

Successful 5-fluorouracil (5-FU) infusion re-challenge in a metastatic colorectal cancer patient with coronary artery disease who experienced symptoms consistent with coronary vasospasm during first 5-FU infusion

5-fluorouracil (5-FU) is an important component of chemotherapy for metastatic colon cancer and can be administered as an intravenous infusion or bolus. Coronary vasospasm is a known complication of infusional and bolus 5-FU administration. In patients who experience coronary vasospasm, 5-FU is often discontinued. Several cases of successful re-challenge with bolus 5-FU, utilizing calcium channel blockers (CCBs) and nitrates to prophylaxis against coronary vasospasm recurrence, have been reported in the literature. However, since there is increased variability of time to symptom onset with infusional 5-FU, re-challenge with infusional 5-FU has not been widely studied. Given potential differences in the toxicity profile and exposure time, infusional may be more appropriate than bolus for some patients. Here we report successful re-challenge with infusional 5-FU, following coronary vasospasm during the first cycle of 5-FU plus leucovorin plus oxaliplatin chemotherapy, in a patient with metastatic colon cancer and coronary artery disease (CAD). The 5-FU re-challenge plan included dose reduction, CCB and nitrate prophylaxis, and telemetry monitoring.

Mechanism of bioactive polysaccharide from Lachnum sp. acts synergistically with 5-fluorouracil against human hepatocellular carcinoma

The antimetabolite 5-fluorouracil (5-FU) is a widely used antitumor agent, however the overall response rate to 5-FU as a single agent is usually limited. Herein, how Lachnum expolysaccharide (LEP-2a), a type of active polysaccharide isolated from Lachnum sp., acted synergistically with 5-FU on HepG2 cells was investigated. It was found that LEP-2a notably enhanced 5-FU sensitivity in HepG2 cells in a synergistic manner. After combination treatment of 5-FU and LEP-2a, Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathway were inactivated. In addition, combination treatment induced generation of reactive oxygen species, decreased the levels of intracellular antioxidant enzymes and triggered mitochondrial apoptosis pathway. Furthermore, 5-FU combined with LEP-2a also resulted in p53 activation and NF-κB inhibition, and cell cycle arrest in the S phase as well as cell metastasis stagnation. Interestingly, LEP-2a treatment also blocked the DNA damage repair procedure. These findings demonstrate that LEP-2a enhanced 5-FU sensitivity and combination of 5-FU and LEP-2a exerts synergistic antitumor efficiency through multiple approaches.

Comparison of definitive chemoradiation with 5-fluorouracil versus capecitabine in anal cancer

BACKGROUND

Capecitabine (Cap) is an established treatment alternative to 5-fluorouracil (5-FU) for chemoradiation in rectal cancer. Few studies have compared the two agents in anal cancer. We compared outcomes and toxicities using Cap versus 5-FU in non-metastatic anal cancer patients at Stanford.

METHODS

All non-metastatic anal cancer patients treated with definitive chemoradiation at Stanford from 1997-2016 were included. Fisher's exact and Mann-Whitney U tests were used to compare nominal and continuous variables. Gray's test was used to compare incidence of recurrence and colostomy, and Log-rank test was used to compare survival.

RESULTS

Sixty-eight patients were included. Thirty-six patients received Cap and 32 received 5-FU (12 received standard 5-FU and 20 received low-dose continuous 5-FU). Patient characteristics were similar between the two groups. There was no difference in the 3-year overall and disease-specific survival between Cap and 5-FU (94% vs. 80%, P=0.197; 100% vs. 86%, P=0.051). Overall incidence of recurrence was equivalent between Cap and 5-FU (11% vs. 13%, P=0.703), but incidence of locoregional recurrence was higher in the 5-FU group (0% vs. 13%, P=0.042); patients treated with Cap had longer recurrence-free intervals (18 vs. 6 months, P=0.400), and all recurrences were distant. More colostomies were needed with 5-FU (3% vs. 13%, P=0.133). Toxicities were similar between the two groups. The most common grade ≥2 toxicities were dermatitis (77%), anal pain (78%), and diarrhea (56%).

CONCLUSIONS

Overall survival (OS), cancer-specific survival and incidence of recurrence were equivalent between Cap and 5-FU in anal cancer. Patients treated with Cap had statistically significant lower incidence of loco-regional relapses.

Hepatitis C Virus-Induced FUT8 Causes 5-FU Drug Resistance in Human Hepatoma Huh7.5.1 Cells

Hepatitis C virus (HCV) is a major cause of human chronic liver disease and hepatocellular carcinoma. Our recent studies showed that α1,6-fucosyltransferase (FUT8), a key glycosyltransferase, was the most up-regulated glycosyltransferase after the HCV infection of human hepatocellular carcinoma Huh7.5.1 cells. Here, we further studied the effects and possible mechanism of FUT8 on the proliferation of HCV and chemotherapy-resistance of HCV-infected Huh7.5.1 cells. The effects of FUT8 on the proliferation and drug resistance of HCV-infected Huh7.5.1 cells were analyzed by flow cytometry analysis (FCM), quantitative real-time polymerase chain reaction (qRT-PCR), Western blot analysis and lactate dehydrogenase (LDH) release assay. Results: We found that FUT8 not only promoted Huh7.5.1 proliferation by activating PI3K-AKT-NF-κB signaling, but also stimulated the expression of the drug-resistant proteins P-glycoprotein (P-gp) and multidrug resistance related protein 1 (MRP1) and enhanced the 5-fluorouracil (5-FU) chemo-resistance of Huh7.5.1 cells. Silencing of FUT8 reduced the cell proliferation and increased the 5-FU sensitivity of HCV-infected Huh7.5.1 cells. Inhibition of P-gp and MRP1 increased the 5-FU drug sensitivity in HCV infected Huh7.5.1 cells. HCV-induced FUT8 promotes proliferation and 5-FU resistance of Huh7.5.1 cells. FUT8 may serve as a therapeutic target to reverse chemotherapy resistance in HCV-infected Huh7.5.1 cells.

Inhibitory effects and molecular mechanisms of pentagalloyl glucose in combination with 5-FU on aggressive phenotypes of HepG2 cells

This study examined the inhibition and mechanism of natural product pentagalloyl glucose (PGG) against HepG2 cells and determined the effects of its combination with the clinical chemotherapeutic drug, 5-FU. PGG was found to inhibit the proliferation, migration and invasion of HepG2 cells, induced G1 arrest and apoptosis in both concentration- and time- dependent manners. The combination of PGG and 5-FU had synergistic effects on reversal the aggressive phenotypes of HepG2 cells, increasing the proportion of Bax/Bcl-2, promoting the activation of caspase-9 and caspase-3, and inducing apoptosis. This combination upregulated P27 and cyclin B1, and downregulated cyclin E1, leading to G1 phase arrest. The combination significantly downregulated MDR1 and LRP1, suggesting the potential to reverse the resistance to 5-FU.

Additional Chemotherapy with 5-FU plus Leucovorin between Preoperative Chemoradiotherapy and Surgery Improved Treatment Outcomes in Patients with Advanced Rectal Cancer

Purpose: The aim of the preliminary study was to evaluate the efficacy and safety of 4-week chemotherapy with 5-Fluorouracil and leucovorin (LV5FU2) during the resting periods between preoperative CRT and surgery in patients with LARC. Materials and Methods: Standard preoperative CRT was delivered to the entire pelvis at a total dose of 5040 Gy of radiation with concurrent 5-FU or capecitabine for 6 weeks. Twenty-three patients received additional preoperative chemotherapy with two cycles of 5-FU and LV (LV 200 mg/m2 and 5-FU bolus 400 mg/m2 on day 1, and 5-FU infusion 2400 mg/m2 for 46 hrs, every 2 weeks) after preoperative CRT. Surgery was performed at 2-4 weeks following the completion of preoperative chemotherapy. Results: Between May 2013 and January 2015, 23 patients underwent preoperative CRT, with additional chemotherapy and surgery, and 23 patients completed the scheduled treatment. The median follow-up duration was 42.0 months. The tumor down-staging rate was observed in 65.2%, and pathologic complete remission (pCR) was noted in 5 patients (21.7%). T and N down-staging were observed in 16 (69.6%) and 14 (60.9%) patients, respectively. The four-year disease-free survival (DFS) rate was 73.9% and the four-year overall survival (OS) rate was 90.9% in patients who received additional chemotherapy. The four-year DFS rate was 100% in the tumor down-staging group vs. 25.0% in the non-down staging group treated with additional chemotherapy (P <0.001). There was also a significant difference of the four-year OS rate 100% in the tumor down-staging group compared with 71.4% in the non-down staging group (P = 0.031). Conclusions: This preliminary study showed that additional preoperative chemotherapy with LV5FU2 was well tolerable and had an improvement in the downstaging rate and survival. Randomized controlled trial of this strategy is encouraged for definitive conclusions.

Functional significance of Hippo/YAP signaling for drug resistance in colorectal cancer

Colorectal cancer is a leading cause of cancer-related death worldwide. While early stage colorectal cancer can be removed by surgery, patients with advanced disease are treated by chemotherapy, with 5-Fluorouracil (5-FU) as a main ingredient. However, most patients with advanced colorectal cancer eventually succumb to the disease despite some responded initially. Thus, identifying molecular mechanisms responsible for drug resistance will help design novel strategies to treat colorectal cancer. In this study, we analyzed an acquired 5-FU resistant cell line, LoVo-R, and determined that elevated expression of YAP target genes is a major alteration in the 5-FU resistant cells. Hippo/YAP signaling, a pathway essential for cell polarity, is an important regulator for tissue homeostasis, organ size, and stem cells. We demonstrated that knockdown of YAP1 sensitized LoVo-R cells to 5-FU treatment in cultured cells and in mice. The relevance of our studies to colorectal cancer patients is reflected by our discovery that high expression of YAP target genes in the tumor was associated with an increased risk of cancer relapse and poor survival in a larger cohort of colorectal cancer patients who underwent 5-FU-related chemotherapy. Taken together, we demonstrate a critical role of YAP signaling for drug resistance in colorectal cancer.

The Herb-Drug Pharmacokinetic Interaction of 5-Fluorouracil and Its Metabolite 5-Fluoro-5,6-Dihydrouracil with a Traditional Chinese Medicine in Rats

Background: Xiang-Sha-Liu-Jun-Zi-Tang (XSLJZT) is the most common traditional formula given to colorectal and breast cancer patients in Taiwan, according to a statistical study of the National Health Insurance Research Database. 5-Fluorouracil (5-FU) is widely used as the first line of treatment for colorectal cancer. Thus, the aim of study is to investigate the pharmacokinetic interaction of XSLJZT and 5-FU. Methods: To investigate the herb–drug interaction of XSLJZT with 5-FU as well as its metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) using pharmacokinetics, a high-performance liquid chromatography (HPLC) system coupled with a photodiode array detector was developed to monitor 5-FU and 5-FDHU levels in rat blood. Rats were divided into three cohorts, one of which was administered 5-FU (100 mg/kg, iv—intravenous) alone, while the other two groups were pretreated with low and high doses of XSLJZT (600 mg/kg/day or 2400 mg/kg/day for 5 consecutive days) in combination with 5-FU. Results: The results demonstrated that 5-FU level was not significantly different between the group treated with only 5-FU and the group pretreated with a normal dose of XSLJZT (600 mg/kg/day). However, pharmacokinetic analysis revealed that pretreatment with a high dose of XSLJZT (2400 mg/kg/day) extended the residence time and increased the volume of distribution of 5-FU. No significant distinctions were found in 5-FDHU pharmacokinetic parameters at three doses of XSLJZT. Conclusions: Overall, the pharmacokinetic results confirm the safety of coadministering 5-FU with XSLJZT, and provide practical dosage information for clinical practice.

Fluoropyrimidine-induced cardiac toxicity: challenging the current paradigm

BACKGROUND

Fluoropyrimidine chemotherapy [5-fluorouracil (5-FU) and capecitabine] are commonly used agents in the treatment of various solid malignancies. However, their use has been limited by cardiac toxicity, presenting as a wide spectrum of asymptomatic (e.g., EKG changes) and symptomatic (e.g., chest pain) manifestations related to coronary vasospasm leading to myocardial ischemia. Historically, patients with suspected coronary vasospasm have been treated with traditional acute ischemic workup and various combinations of anti-anginal therapies. In addition, most patients typically are not rechallenged with fluoropyrimidine after experiencing initial cardiovascular side-effects with resulting interruption of planned chemotherapy regimens.

METHODS

We report a case series of 11 consecutive patients in a single-center with suspected fluoropyrimidine-induced coronary vasospasm who were successfully rechallenged with the culprit drug to allow for planned chemotherapy completion. Our protocol utilized rechallenge with bolus infusional regimen of intravenous fluoropyrimidine chemotherapy and oral capecitabine with cardioprotective pretreatment with two calcium blockers and long-acting oral nitrate therapy.

RESULTS

We were successfully able to continue and complete the previously planned first-line chemotherapy regimen for all 11 patients with minimal therapeutic interruption. There have been no cardiac events or evidence of recurrent coronary spasm after completion of therapy with discontinuation of prophylactic medications upon therapy completion.

CONCLUSIONS

We report a single-institution experience of successful rechallenge with fluoropyrimidines with careful cardiac monitoring and the combined use of calcium channel blockers and long-acting nitrates. With further study, this algorithm can be used to safely continue fluoropyrimidines, a potentially curative regimen in the treatment of many solid tumors.

Peroxisome proliferator activated receptor-gamma stimulation for prevention of 5-fluorouracil-induced oral mucositis in mice

BACKGROUND

Oral mucositis is a side effect of treatment regimens containing 5-fluorouracil (5-FU). The purpose of this study was to present our evaluation to see if rosiglitazone (RGZ) protected normal tissues from chemotherapy-induced oral mucositis.

METHODS

C57BL/6J mice were treated with 5-FU for 5 days, with or without RGZ. Mice were euthanized after 5, 8, 11, or 15 days, and mucosal segments were collected.

RESULTS

The RGZ did not affect the 5-FU-induced decrease in mouse body weight. The 5-FU caused loss of epithelial architecture, collagen fiber impairment, and inflammatory infiltration. The RGZ reduced leukocyte infiltration, preserved tissue structure, and dampened the 5-FU-induced expression of p53 and matrix metalloproteinase (Mmp)-2 after 5 days, and of Mmp-2 and interleukin (Il-1β after 15 days. The RGZ inhibited the 5-FU-induced increase of transforming growth factor-beta (TGF-β) and nuclear factor-kappa B (NF-κB) proteins and restored collagen protein levels.

CONCLUSION

The RGZ had a protective effect on oral mucosa damaged by chemotherapy. These data encourage the further study of RGZ for the prevention of 5-FU-induced mucositis in patients with cancer.

Pressure responsive nanogel base on Alginate-Cyclodextrin with enhanced apoptosis mechanism for colon cancer delivery

5-Fluorouracil (5-Fu) commonly use in the treatment of different kinds of cancer, but limited cellular uptake and death is still a problem. Herein, we report a simple process for the synthesis of pressure-sensitive nanogels that indicate to be appropriate in the delivery of 5-Fu. The hydrogels (Al-CD) prepare by crosslinking of alginate (Al) with modified beta Cyclodextrin (β-CD) as Crosslinker. Next, nanoparticles obtaine by an emulsification method. 5-Fu as model drug loades into the Al-CD nanogels easily by mixing it in aqueous solution with the nanoparticles. The results revealed that the Al-CD nanogels are cytocompatible. They have also a noticeable drug encapsulation (82.1 ±5.7%) while they can release (in vitro controlled) 5-Fu in conditions that imitate the intravascular pressure conditions. These nanogels can rapidly be taken up by HT-29 cells (a colon cell line). In addition, a higher 5-Fu intracellular accumulation and a significant cell death extension by apoptosis mechanism is notice when compare with free 5-Fu. Accordingly, the developed nanogels can be employe as an excellent candidate to overcome the inefficiency of 5-Fu in anticancer treatments and possibly can employe for further evaluation as a chemotherapical agent in applications beyond cancer. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 349-359, 2018.

Translationally controlled tumour protein TCTP is induced early in human colorectal tumours and contributes to the resistance of HCT116 colon cancer cells to 5-FU and oxaliplatin

Background

Translationally controlled tumour protein TCTP is an anti-apoptotic protein frequently overexpressed in cancers, where high levels are often associated with poor patient outcome. TCTP may be involved in protecting cancer cells against the cytotoxic action of anti-cancer drugs. Here we study the early increase of TCTP levels in human colorectal cancer (CRC) and the regulation of TCTP expression in HCT116 colon cancer cells, in response to treatment with the anti-cancer drugs 5-FU and oxaliplatin.

Methods

Using immunohistochemistry, we assessed TCTP levels in surgical samples from adenomas and adenocarcinomas of the colon, compared to normal colon tissue. We also studied the regulation of TCTP in HCT116 colon cancer cells in response to 5-FU and oxaliplatin by western blotting. TCTP mRNA levels were assessed by RT-qPCR. We used mTOR kinase inhibitors to demonstrate mTOR-dependent translational regulation of TCTP under these conditions. Employing the Real-Time Cell Analysis (RTCA) System and the MTS assay, we investigated the effect of TCTP-knockdown on the sensitivity of HCT116 cells to the anti-cancer drugs 5-FU and oxaliplatin.

Results

1. TCTP levels are significantly increased in colon adenomas and adenocarcinomas, compared to normal colon tissue. 2. TCTP protein levels are about 4-fold upregulated in HCT116 colon cancer cells, in response to 5-FU and oxaliplatin treatment, whereas TCTP mRNA levels are down regulated. 3. mTOR kinase inhibitors prevented the up-regulation of TCTP protein, indicating that TCTP is translationally regulated through the mTOR complex 1 signalling pathway under these conditions. 4. Using two cellular assay systems, we demonstrated that TCTP-knockdown sensitises HCT116 cells to the cytotoxicity caused by 5-FU and oxaliplatin.

Conclusions

Our results demonstrate that TCTP levels increase significantly in the early stages of CRC development. In colon cancer cells, expression of this protein is largely upregulated during treatment with the DNA-damaging anti-cancer drugs 5-FU and oxaliplatin, as part of the cellular stress response. TCTP may thus contribute to the development of anti-cancer drug resistance. These findings indicate that TCTP might be suitable as a biomarker and that combinatorial treatment using 5-FU/oxaliplatin, together with mTOR kinase inhibitors, could be a route to preventing the development of resistance to these drugs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-017-0164-3) contains supplementary material, which is available to authorized users.

Sensitization of 5-Fluorouracil-Resistant SNUC5 Colon Cancer Cells to Apoptosis by α-Mangostin

5-fluorouracil (5-FU) is a chemotherapeutic agent commonly used for treatment of solid tumors, including colorectal cancer. However, chemoresistance against 5-fluorouracil (5-FU) often limits its success for chemotherapy and, therefore, finding out appropriate adjuvant(s) that might overcome chemoresistance against 5-FU bears a significant importance. In the present study, we have found that α-mangostin can sensitize 5-FU-resistant SNUC5/5-FUR colon cancer cells to apoptosis. Exposure of α-mangostin induced significant DNA damages and increased the intracellular 8-hydroxyguanosine (8-OH-G) and 4-hydroxynonenal (4-HNE) levels in SNUC5 and SNUC5/5-FUR cells. Western blot analysis illustrated that α-mangostin-induced apoptosis was mediated by the activation of the extrinsic and intrinsic pathways in SNUC5/5-FUR cells. In particular, we observed that Fas receptor (FasR) level was lower in SNUC5/5-FUR cells, compared with SNUC5 cells and that silencing FasR attenuated α-mangostin-mediated apoptosis in SNUC5/5-FUR cells. Together, our study illustrates that α-mangostin might be an efficient apoptosis sensitizer that can overcome chemoresistance against 5-FU by activating apoptosis pathway.

A comparison between 5-fluorouracil/mitomycin and capecitabine/mitomycin in combination with radiation for anal cancer

BACKGROUND

There are no randomized phase III trials comparing 5-fluorouracil/mitomycin (FM) versus capecitabine/mitomycin (CM) in combination with radiotherapy (RT) for locally advanced anal cancer. We aim to evaluate the outcomes of patients treated with FM and CM at our institution.

METHODS

Patients with stage I-III anal cancer who initiated curative-intent RT (50-54 Gy) with either CM or FM between 1998 and 2013 at the BC Cancer Agency were reviewed. Cox proportional models were used to analyze the impact of regimen on disease-free survival (DFS) and anal cancer-specific survival (ACSS).

RESULTS

A total of 300 patients were included. Baseline characteristics were well-distributed between the groups. A total of 194 patients (64.6%) received FM and 106 (35.3%) CM. The 2-year DFS was 79.7% for CM [95% confidence intervals (95% CI), 71.1-88.3%] and 78.8% for FM (95% CI, 73-84.6%); 2-year ACSS was 88.7% for CM (95% CI, 81.8-95.5%) and 87.5% for FM (95% CI, 82.8-92.2%). On multivariate analysis, only HIV status, clinical T size (≤5 vs. >5 cm), and N status (negative vs. positive) remained as significant prognostic factors for both DFS and ACSS. Chemotherapy regimen (CM vs. FM) had no impact on either DFS [P=0.995; hazard ratios (HR) =0.99; 95% CI, 0.57-1.74] or ACSS (P=0.847; HR =0.93; 95% CI, 0.46-1.86).

CONCLUSIONS

In our population-based study, CM and FM concomitant with RT achieved similar DFS and ACSS. Substitution of capecitabine for infusional 5-FU may therefore be a reasonable option for patients and physicians who prefer to avoid the inconvenience and potential complications of a central infusional device.

Human papillomavirus oncoproteins differentially modulate epithelial-mesenchymal transition in 5-FU-resistant cervical cancer cells

Etiological role of viral proteins E6 and E7 of high-risk HPV in cervical carcinogenesis is well established. However, their contribution in chemoresistance and epithelial-mesenchymal transition (EMT) that leads to advanced metastatic lesions and chemoresistance is poorly defined. In the present study, contribution of viral oncoproteins in acquisition of EMT character during onset of chemoresistance was assessed. A chemoresistant cell line (SiHaCR) was developed from an established HPV16-positive cervical cancer cell line, SiHa, by escalating selection pressure of 5-fluorouracil (5-FU). Expression of Survivin, ABCG2, Snail, Slug, Twist, and Vimentin was examined in SiHa and SiHaCR cells by reverse transcriptase-PCR (RT-PCR) and immunoblotting assays. Mesenchymal phenotype in SiHaCR cells was confirmed by assessment of migration and invasion potentials. SiHaCR cells displayed elevated level of functional and molecular markers associated with chemoresistance (Survivin, ABCG2) and EMT (Snail, Slug, Twist, Vimentin) and reduced E-cadherin. SiHaCR also showed increased levels of HPV16 E6 and E7 transcripts. Specific silencing of HPV16 E6, but not E7 using corresponding siRNA, demonstrated a differential involvement of HPV oncogenes in manifestation of EMT. HPV16 E6 silencing resulted in reduction of Slug and Twist expression. However, the expression of Snail and Vimentin was only marginally affected. In contrast, there was an increase in the expression of E-cadherin. A reduced migration and invasion capabilities were observed only in E6-silenced SiHaCR cells, which further confirmed functional contribution of HPV16 E6 in manifestation of EMT. Taken together, our study demonstrated an active involvement of HPV16 E6 in regulation of EMT, which promotes chemoresistance in cervical cancer.

Improved Chemotherapeutic Activity by Morus alba Fruits through Immune Response of Toll-Like Receptor 4

Morus alba L. fruits have long been used in traditional medicine by many cultures. Their medicinal attributes include cardiovascular, hepatoprotective, neuroprotective and immunomodulatory actions. However, their mechanism of macrophage activation and anti-cancer effects remain unclear. The present study investigated the molecular mechanisms of immune stimulation and improved chemotherapeutic effect of M. alba L. fruit extract (MFE). MFE stimulated the production of cytokines, nitric oxide (NO) and tumor necrosis factor-α (TNF-α) and tumoricidal properties of macrophages. MFE activated macrophages through the mitogen-activated protein kinase (MAPKinase) and nuclear factor-κB (NF-κB) signaling pathways downstream from toll-like receptor (TLR) 4. MFE was shown to exhibit cytotoxicity of CT26 cells via the activated macrophages, even though MFE did not directly affect CT26 cells. In a xenograft mouse model, MFE significantly enhanced anti-cancer activity combined with 5-fluorouracil and markedly promoted splenocyte proliferation, natural killer (NK) cell activity, cytotoxic T lymphocyte (CTL) activity and IFN-γ production. Immunoglobulin G (IgG) antibody levels were significantly increased. These results indicate the indirect anti-cancer activity of MFE through improved immune response mediated by TLR4 signaling. M. alba L. fruit extract might be a potential anti-tumor immunomodulatory candidate chemotherapy agent.

Structural basis of mapping the spontaneous mutations with 5-flurouracil in uracil phosphoribosyltransferase from Mycobacterium tuberculosis

Tuberculosis (TB) remains the second leading cause of death from an infectious disease globally, despite the incessant efforts to control it. Research and development into new TB medicines is imperative for effective TB control; however, new strategies for the rational use of existing drugs, such as through the identification of new drug targets, could also significantly enhance this process. Key enzymes involved in the essential metabolic and regulatory pathways are usually sought in the pursuit of potential drug targets. Uracil phosphoribosyltransferase (UPRT) is a key salvage pathway enzyme in the synthesis of uridine 5'-monophosphate (UMP) and a probable target of 5-fluorouracil (5-FU) in Mycobacterium tuberculosis (Mtb). To date, there is no structure available for UPRT from Mtb (MtUPRT) that would assist in the identification of appropriate inhibitors for the enzyme. Here we report the structure of MtUPRT along with its spontaneous mutational studies in the presence of 5-FU. We further mapped these four single nucleotide polymorphisms (SNPs) onto the MtUPRT structure, with two residues found to be conserved among the MtUPRT homologs. Notably, none of these SNPs are located in the 5-FU binding pocket. However, the mutants harboring these mutations showed increased MICs (minimum inhibitory concentration) as compared to wild type strains. The present study will aid in the screening of inhibitors of MtUPRT and thus assist in TB drug design and development.

Variability in the anti-tumor effect of tegafur-uracil depending on histologic types of lung cancer

BACKGROUND

Tegafur-uracil (UFT) is an anticancer agent that inhibits thymidylate synthase (TS). The degree of TS expression in primary lung cancer (LC) is different according to histologic cell type. In this study, we examined the variability of the anti-tumor efficacy of UFT monotherapy depending on histological subtypes of LC.

METHODS

In the current single-institution, retrospective study, we assigned the patients with LC to three histologic groups [the squamous (Sq) non-small cell lung cancer (NSCLC)] group, the non-Sq NSCLC group and the SCLC group] and then compared the clinical response to UFT monotherapy between the three groups.

RESULTS

Our clinical series of 149 patients include 54 cases of Sq NSCLC, 67 cases of non-Sq NSCLC and 28 cases of SCLC. For Sq NSCLC, non-Sq NSCLC and SCLC group, the overall response rates (ORRs) were 1%, 1% and 0% (P=0.522), respectively. The disease control rates (DCRs) were 38.9%, 31.3% and 10.7% (P=0.012), respectively. The median progression-free survivals (PFSs) were 2.68, 2.25 and 1.46 months (P=0.004 for three groups and P=0.773 for two groups except for the SCLC group at the log-rank test), respectively. There was no significant difference between the groups in median overall survival (OS).

CONCLUSIONS

Our results indicate that the degree of the anti-tumor effect of UFT was higher in patients with NSCLC as compared with SCLC. But it showed no significant difference between the patients with Sq NSCLC and those with non-Sq NSCLC.

Concurrent chemoradiotherapy with protracted infusion of 5-fluorouracil (5-FU) and cisplatin for locally advanced resectable esophageal cancer

BACKGROUND

Neoadjuvant concurrent chemoradiotherapy (CCRT) has become the standard treatment for esophageal cancer (EC) in North America. The cisplatin/5-flurouracil (5-FU) combination has been the most commonly used regimen. For the last 15 years we incorporated a daily continuous infusion of 5-FU and 2 doses of cisplatin into our neoadjuvant CCRT for potentially resectable EC.

PATIENTS AND METHODS

Between July 1997 and June 2012, 129 patients with locally advanced EC (T3 or N1 and higher), received neoadjuvant CCRT with cisplatin 75 mg/m(2) on day 1 and day 29 and continuous infusion of 5-FU (225 mg/m(2)/day) on the days of radiation.

RESULTS

The median age of patients was 63 years, 85% had adenocarcinoma, 29, 74 and 26 patients had stage II, III and IVa disease respectively, 110 patients had N1 disease based on the American Joint Committee on Cancer (AJCC) 6(th) edition, 118 patients experienced weight loss during treatment. All patients completed treatment. Treatment was well tolerated with 14% of patients having ≥ grade 3 toxicity and 18 patients requiring hospital admission. Sixty-four percent of patients had surgical resection following CCRT, with disease progression and patient refusal being the most common reasons for not proceeding with surgery. An R0 resection was achieved in 96% of patients. A pathological complete response (pCR) was achieved in 45% of patients. With a median follow up of 26 months (1.2-144 months), 48/129 patients recurred and 60/129 died of their disease.

CONCLUSIONS

Our study has its limitation, however, and compared to the conventional chemotherapy regimens containing the cisplatin/5-FU doublet, our treatment strategy for locally advanced EC CCRT seems to be feasible and well tolerated.

A comparative study of the safety and efficacy effect of 5-fluorouracil or mitomycin C mounted biological delivery membranes in a rabbit model of glaucoma filtration surgery

Purpose

To investigate the potential usage of biological delivery membranes containing mitomycin C (MMC) or 5-fluorouracil (5-FU) in the construction of glaucoma-filtering blebs, and to evaluate their safety and efficacy.

Methods

Chitosan was selected as the biological membrane carrier to prepare sustained-released membranes. Twelve micrograms of 5-FU or MMC was covalently conjugated onto the membranes by solvent volatilization. Rabbits underwent glaucoma filtration surgery and were randomly allocated into one of the four treatment regimens: glaucoma filtration operation with no implantation of chitosan membrane group (as control), drug-free chitosan membrane implantation group (blank/placebo group), membrane containing 5-FU treatment group (5-FU group), and membrane containing MMC treatment group (MMC group). Each group consisted of 12 rabbits. Intraocular pressure (IOP) was measured and evaluated over a 28-day period follow-up preoperatively, then after surgery on days 1, 3, 5, 7, 14, 21, and 28 by Tono-Pen. The aqueous humor was analyzed in each experimental and control groups at days 4, 6, 8, 10, 12, 14, 16, and 20 after operation. Bleb survival and anterior segment were examined with a slit lamp microscope and photographed simultaneously. Two rabbits from each group were killed on day 28 and eight eye samples obtained for histopathological study. Corneas and lenses were examined by transmission and scanning electron microscopy.

Results

Both 5-FU and MMC significantly prolonged bleb survival compared with control groups. The filtering bleb’s survival period was significantly more prolonged in the MMC and 5-FU groups (maintained 14 days) than the other two groups (maintained 7 days). Significantly lower IOP was observed within the control, blank, and 5-FU groups after surgery on day 14 compared with that before operation, with F-values of 6.567, 11.426, and 13.467, respectively (P < 0.01). The most significant lower IOP was recorded in the MMC group on day 28 postoperation (F-value 26.866, P < 0.01). No obvious abnormalities were found in cornea or anterior lens capsule 28 days after surgery.

Conclusion

The study provided evidence that 5-FU and MMC biological delivery membranes could significantly improve the outcome of filtering procedures, the survival of the bleb, and maintenance of lower IOP. MMC membrane is superior to 5-FU, with regard to the more effective reduction of IOP. The results indicated a safe and effective treatment strategy in glaucoma surgery.

Effects of anticancer agents on cell viability, proliferative activity and cytokine production of peripheral blood mononuclear cells

We investigated the effects of anticancer agents on peripheral blood mononuclear cells for the purpose of providing data to support new translational chemoimmunotherapy regimens. Peripheral-blood mononuclear cells were treated with one of four anticancer agents (5-fluorouracil, irinotecan, cisplatin, and gemcitabine) for 2 h, after which cell viability was determined. For assessment of effects of each drug on proliferation and cytokine production, cells were stimulated with phytohemagglutinin for 48 h. As a result, the anticancer agents did not affect cell viability. Cell proliferation was unaffected by 5-fluorouracil and irinotecan but inhibited by cisplatin and gemcitabine. Treatment with gemcitabine enhanced the production of IFN-γ and decreased the number of regulatory T cells. gemcitabine treatment increased IFN-γ production among CD4 T cells but not among CD8 T cells. The results indicated that GEM had immunoregulatory properties that might support immune response against cancer. This finding has implications for designing chemoimmunotherapy strategies.

Preparation and distribution of 5-fluorouracil 125I sodium alginate-bovine serum albumin nanoparticles

AIM: To prepare 5-FU sodium alginate ¹²⁵I bovine serum albumin nanoparticles (BSA NP), to de-termine the radioactive count in different organs of rats at different time points after oral adminis-tration of 5-FU ¹²⁵I sodium alginate-BSA NP and to calculate the kinetic parameters of its metabolism.

METHODS: Emulsion solidification method was used to prepare 5-FU ¹²⁵I sodium alginate-BSA NP, and to determine its diameter under trans-mission electronic microscope (TEM). Then the rate of NP and external drug releasing velocity were measured. Radioactive counting in different organs of rats wa s made after oral adminis-tration of the NP by GAMA Counter, and the ki-netic para meters of drug metabolism were calcu-lated by handling the data with the two-depart-ment model.

RESULTS: The average arithmatic diameter of the NP was 166 nm ± 34 nm, the rate of 5-FU was 32.8% and the cumulative external releasing ra-tio amounted to 84.0% within 72 hours. The NP was mainly distributed in the liver, spleen, lungs and kidneys after NP oral administration to rats. The mic ro-radioautographic experiment showed that NP was distributed in the Kupffers cells of liver, liver parenchymal cells and the phagocytes of spleen and lungs. The kinetic pa-rameters of matabolism were: T_1/2 = 9.42 h, C_max =2.45 × 10⁷ Bq, T_max = 2.18 h, AUC = 148 × 10⁹ Bq.

CONCLUSION: NP is difficult to pass through the blood-cerebral barrier,and ¹²⁵I sodium alginate-BSA NP enters the body circulation by gastroin testinal passage.