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

Pumpless, unidirectional microphysiological system for testing metabolism-dependent chemotherapeutic toxicity

Drug development is often hindered by the failure of preclinical models to accurately assess and predict the efficacy and safety of drug candidates. Body-on-a-chip (BOC) microfluidic devices, a subset of microphysiological systems (MPS), are being created to better predict human responses to drugs. Each BOC is designed with separate organ chambers interconnected with microfluidic channels mimicking blood recirculation. Here, we describe the design of the first pumpless, unidirectional, multiorgan system and apply this design concept for testing anticancer drug treatments. HCT-116 colon cancer spheroids, HepG2/C3A hepatocytes, and HL-60 promyeloblasts were embedded in collagen hydrogels and cultured within compartments representing "colon tumor", "liver," and "bone marrow" tissue, respectively. Operating on a pumpless platform, the microfluidic channel design provides unidirectional perfusion at physiologically realistic ratios to multiple channels simultaneously. The metabolism-dependent toxic effect of Tegafur, an oral prodrug of 5-fluorouracil, combined with uracil was examined in each cell type. Tegafur-uracil treatment induced substantial cell death in HCT-116 cells and this cytotoxic response was reduced for multicellular spheroids compared to single cells, likely due to diffusion-limited drug penetration. Additionally, off-target toxicity was detected by HL-60 cells, which demonstrate that such systems can provide useful information on dose-limiting side effects. Collectively, this microscale cell culture analog is a valuable physiologically-based pharmacokinetic drug screening platform that may be used to support cancer drug development.

Evaluation of hepatic drug-metabolism for glioblastoma using liver-brain chip

Glioma is one of the most aggressive and highly fatal diseases with an extremely poor prognosis. Considering the poor clinical response to therapy in glioma, it is urgent to establish an in vitro model to facilitate the screening and assessment of anti-brain-tumor drugs. The blood-brain barrier (BBB), as well as liver metabolism plays an important role in determining the pharmacological activity of many anti-brain-tumor drugs. In this work, we designed a multi-interface liver-brain chip integrating co-culture system to assess hepatic metabolism dependent cytotoxicity of anti-brain-tumor drug in vitro. This microdevice composed of three microchannels which were separated by porous membrane and collagen. HepG2 and U87 cells were cultured in separated channels as mimics of liver and glioblastoma. Brain microvascular endothelial cells (BMECS) and cerebral astrocytes were co-cultured on collagen to mimic the brain microvascular endothelial barrier. Three common anti-tumor drugs, paclitaxel (PTX), capecitabine (CAP) and temozolomide (TMZ), were evaluated on this chip. In integrated liver-brain chip, liver enhanced the cytotoxicity of CAP on U87 cells by 30%, but having no significant effect on TMZ. The BBB decreased the cytotoxicity of PTX by 20%, while no significant effects were observed on TMZ and CAP, indicating the importance of liver metabolism and blood-brain barrier on the evaluation of anti-brain-tumor drugs. This work provides a biomimetic liver-brain model to mimic the physiological and pharmacological processes in vitro and presents a simple platform for long-term cell co-culture, drug delivery and metabolism, and real-time analysis of drug effects on brain cancer.

In silico design and evaluation of novel 5-fluorouracil analogues as potential anticancer agents

5-fluorouracil (5-FU) has been shown to have suffered from resistance which demands a solution entailing the development of 5-FU analogues. Our study aims to design a number of analogues of 5-FU and evaluate their effectiveness against thymidylate synthase (TS) in silico compared to parent 5-FU with an effort to obtain better hit(s). All the molecules were optimized by molecular mechanics method utilizing MM2 forcefield parameters. Molecular docking of these molecules against TS was performed to catch on the binding strength of these molecules, determination of binding energy & interaction types of each ligand-target complex as well as subsequent analysis. PRA10 showed highest binding affinity (-9.1 Kcal/mol). Although binding energy of PRA6 & PRA14 are slightly lower than PRA10, they can be of special interest since they interact with crucial amino acids for binding and exhibit substantial non-bonded interactions. Residue analysis revealed that Arg50A, Arg175B, Arg215A, Ser216A, Arg176B and Asn226A of TS active site were crucial for binding/interaction. The best scored drug candidates demonstrated considerable pharmacokinetic as well as druglike properties. The present study also revealed that PRA6, PRA10 and PRA14 can be potential anticancer drugs for further development.

Dietary serine-microbiota interaction enhances chemotherapeutic toxicity without altering drug conversion

The gut microbiota metabolizes drugs and alters their efficacy and toxicity. Diet alters drugs, the metabolism of the microbiota, and the host. However, whether diet-triggered metabolic changes in the microbiota can alter drug responses in the host has been largely unexplored. Here we show that dietary thymidine and serine enhance 5-fluoro 2'deoxyuridine (FUdR) toxicity in C. elegans through different microbial mechanisms. Thymidine promotes microbial conversion of the prodrug FUdR into toxic 5-fluorouridine-5'-monophosphate (FUMP), leading to enhanced host death associated with mitochondrial RNA and DNA depletion, and lethal activation of autophagy. By contrast, serine does not alter FUdR metabolism. Instead, serine alters E. coli's 1C-metabolism, reduces the provision of nucleotides to the host, and exacerbates DNA toxicity and host death without mitochondrial RNA or DNA depletion; moreover, autophagy promotes survival in this condition. This work implies that diet-microbe interactions can alter the host response to drugs without altering the drug or the host.

MFP-FePt-GO Nanocomposites Promote Radiosensitivity of Non-Small Cell Lung Cancer Via Activating Mitochondrial-Mediated Apoptosis and Impairing DNA Damage Repair

Background: Recent advances in nanomedicine provided promising alternatives for tumor treatment to improve the survival and life quality of cancer patients. This study was designed to explore the insight mechanisms of the anti-tumor effects of the novel nanocomposites (NCs) MFP-FePt-GO with non-small cell lung cancer (NSCLC).

Methods: A chemical co-reduction method was applied to the synthesis process of MFP-FePt-GO NCs. The chemical synthesis efficiency and morphology of the NCs were measured with spectroscope and transmission electron microscope. Colony formation assay and cell apoptosis were conducted to assess the radiosensitivity effect of NCs with radiation. Then, we detected cell mitochondrial membrane potential and reactive oxygen species (ROS) level by flow cytometry to further explore the cause of cell death. Immunofluorescence staining and Confocal were carried out to determine the DNA damage repair. A Lewis lung carcinoma animal model was used to measure safety and anti-tumor efficiency in vivo.

Results: The novel NCs MFP-FePt-GO designed on a lamellar-structure magnetic graphene oxide and polyethylene glycol drug delivery system was synthesized and functionalized for co-delivery of metronidazole and 5-fluorouracil. While no severe allergies, liver and kidney damage, or drug-related deaths were observed, MFP-FePt-GO NCs promoted radiosensitivity of NSCLC cells both in vivo and in vitro. It improved the effects of radiation via activating intrinsic mitochondrial-mediated apoptosis and impairing DNA damage repair. This NCs also induced a ROS burst, which suppressed the antioxidant protein expression and induced cell apoptosis. Furthermore, MFP-FePt-GO NCs prevented NSCLC cell migration and invasion.

Conclusion: MFP-FePt-GO NCs showed a synergistic anti-tumor effect with radiation to eliminate tumors. With good safety and efficacy, this novel NCs could be a potential radiosensitive agent for NSCLC patients.

Efficacy of adjuvant chemotherapy with S-1 in stage II oral squamous cell carcinoma patients: A comparative study using the propensity score matching method

It has been reported that 20% of early-stage oral squamous cell carcinoma (OSCC) patients treated with surgery alone (SA) may exhibit postoperative relapse within 2–3 years and have poor prognoses. We aimed to determine the safety of S-1 adjuvant chemotherapy and the potential differences in the disease-free survival (DFS) between patients with T2N0 (stage II) OSCC treated with S-1 adjuvant therapy (S-1) and those treated with SA. This single-center retrospective cohort study was conducted at Kumamoto University, between April 2004 and March 2012, and included 95 patients with stage II OSCC. The overall cohort (OC), and propensity score-matched cohort (PSMC) were analyzed. In the OC, 71 and 24 patients received SA and S-1, respectively. The time to relapse (TTR), DFS, and overall survival were better in the S-1 group, but the difference was not significant. In the PSMC, 20 patients each received SA and S-1. The TTR was significantly lower in the S-1 group than in the SA group, while the DFS was significantly improved in the former. S-1 adjuvant chemotherapy may be more effective than SA in early-stage OSCC.

SLX4IP and telomere dynamics dictate breast cancer metastasis and therapeutic responsiveness

An unbiased genetic screen established SLX4IP as an essential driver of telomere maintenance mechanism identity, metastatic progression, and therapeutic response of breast cancers.

Metastasis is the leading cause of breast cancer-related death and poses a substantial clinical burden owing to a paucity of targeted treatment options. The clinical manifestations of metastasis occur years-to-decades after initial diagnosis and treatment because disseminated tumor cells readily evade detection and resist therapy, ultimately giving rise to recurrent disease. Using an unbiased genetic screen, we identified SLX4-interacting protein (SLX4IP) as a regulator of metastatic recurrence and established its relationship in governing telomere maintenance mechanisms (TMMs). Inactivation of SLX4IP suppressed alternative lengthening of telomeres (ALT), coinciding with activation of telomerase. Importantly, TMM selection dramatically influenced metastatic progression and survival of patients with genetically distinct breast cancer subtypes. Notably, pharmacologic and genetic modulation of TMMs elicited telomere-dependent cell death and prevented disease recurrence by disseminated tumor cells. This study illuminates SLX4IP as a potential predictive biomarker for breast cancer progression and metastatic relapse. SLX4IP expression correlates with TMM identity, which also carries prognostic value and informs treatment selection, thereby revealing new inroads into combating metastatic breast cancers.

Promotion of the Warburg effect is associated with poor benefit from adjuvant chemotherapy in colorectal cancer

Metabolic reprogramming, including the Warburg effect, is a hallmark of cancer. Indeed, the diversity of cancer metabolism leads to cancer heterogeneity, but accurate assessment of metabolic properties in tumors has not yet been undertaken. Here, we performed absolute quantification of the expression levels of 113 proteins related to carbohydrate metabolism and antioxidant pathways, in stage III colorectal cancer surgical specimens from 70 patients. The Warburg effect appeared in absolute protein levels between tumor and normal mucosa specimens demonstrated. Notably, the levels of proteins associated with the tricarboxylic citric acid cycle were remarkably reduced in the malignant tumors which had relapsed after surgery and treatment with 5-fluorouracil-based adjuvant therapy. In addition, the efficacy of 5-fluorouracil also decreased in the cultured cancer cell lines with promotion of the Warburg effect. We further identified nine and eight important proteins, which are closely related to the Warburg effect, for relapse risk and 5-fluorouracil benefit, respectively, using a biomarker exploration procedure. These results provide us a clue for bridging between metabolic protein expression profiles and benefit from 5-fluorouracil adjuvant chemotherapy.

5-Fluorouracil as a Tumor-Treating Field-Sensitizer in Colon Cancer Therapy

Colorectal cancer (CRC) is a major cause of mortality that can be treated effectively with chemotherapy and radiotherapy, although resistance to these therapeutic modalities often occurs. Tumor-treating fields (TTFields) can block tumor growth by selectively impairing tumor cell division. In this study, we investigated the mechanism by which 5-fluorouracil (5-FU) sensitizes tumor cells to TTFields. Human HCT116 and SW480 CRC cells were treated with 5-FU and/or TTFields, and characterized in vitro in terms of cell viability, apoptosis through reactive oxygen species production, autophagy, and metastatic potentials. The biological effects of 5-FU and/or TTFields were studied via positron emission tomography and computed tomography on xenograft tumor growth and were confirmed with organoid models of patients. Our results revealed that combination treatment with 5-FU and TTFields increased the efficiency of TTFields therapy in colon cancer cells by downregulating signaling pathways associated with cell proliferation, survival, cell invasion, and migration while upregulating pathways mediating apoptosis and autophagic cell death. The novel mechanistic insights gleaned in this study suggest that combination therapy with TTFields and 5-FU may be effective in treating CRC, although safety and efficacy testing in patients with CRC will need to be performed before this strategy can be implemented clinically for TTF-sensitization.

Metabolic Remodelling: An Accomplice for New Therapeutic Strategies to Fight Lung Cancer

Metabolic remodelling is a hallmark of cancer, however little has been unravelled in its role in chemoresistance, which is a major hurdle to cancer control. Lung cancer is a leading cause of death by cancer, mainly due to the diagnosis at an advanced stage and to the development of resistance to therapy. Targeted therapeutic agents combined with comprehensive drugs are commonly used to treat lung cancer. However, resistance mechanisms are difficult to avoid. In this review, we will address some of those therapeutic regimens, resistance mechanisms that are eventually developed by lung cancer cells, metabolic alterations that have already been described in lung cancer and putative new therapeutic strategies, and the integration of conventional drugs and genetic and metabolic-targeted therapies. The oxidative stress is pivotal in this whole network. A better understanding of cancer cell metabolism and molecular adaptations underlying resistance mechanisms will provide clues to design new therapeutic strategies, including the combination of chemotherapeutic and targeted agents, considering metabolic intervenients. As cancer cells undergo a constant metabolic adaptive drift, therapeutic regimens must constantly adapt.

5-fluorouracil and other fluoropyrimidines in colorectal cancer: Past, present and future

5-Fluorouracil (5-FU) is an essential component of systemic chemotherapy for colorectal cancer (CRC) in the palliative and adjuvant settings. Over the past four decades, several modulation strategies including the implementation of 5-FU-based combination regimens and 5-FU pro-drugs have been developed and tested to increase the anti-tumor activity of 5-FU and to overcome the clinical resistance. Despite the encouraging progress in CRC therapy to date, the patients' response rates to therapy continue to remain low and the patients' benefit from 5-FU-based therapy is frequently compromised by the development of chemoresistance. Inter-individual differences in the treatment response in CRC patients may originate in the unique genetic and epigenetic make-up of each individual. The critical element in the current trend of personalized medicine is the proper comprehension of causes and mechanisms contributing to the low or lack of sensitivity of tumor tissue to 5-FU-based therapy. The identification and validation of predictive biomarkers for existing 5-FU-based and new targeted therapies for CRC treatment will likely improve patients' outcomes in the future. Herein we present a comprehensive review summarizing options of CRC treatment and the mechanisms of 5-FU action at the molecular level, including both anabolic and catabolic ways. The main part of this review comprises the currently known molecular mechanisms underlying the chemoresistance in CRC patients. We also focus on various 5-FU pro-drugs developed to increase the amount of circulating 5-FU and to limit toxicity. Finally, we propose future directions of personalized CRC therapy according to the latest published evidence.

Immune Checkpoint Inhibitors: Basics and Challenges

Cancer is one of the most deadly diseases in the modern world. The last decade has witnessed dramatic advances in cancer treatment through immunotherapy. One extremely promising means to achieve anti-cancer immunity is to block the immune checkpoint pathways - mechanisms adopted by cancer cells to disguise themselves as regular components of the human body. Many review articles have described a variety of agents that are currently under extensive clinical evaluation. However, while checkpoint blockade is universally effective against a broad spectrum of cancer types and is mostly unrestricted by the mutation status of certain genes, only a minority of patients achieve a complete response. In this review, we summarize the basic principles of immune checkpoint inhibitors in both antibody and smallmolecule forms and also discuss potential mechanisms of resistance, which may shed light on further investigation to achieve higher clinical efficacy for these inhibitors.

Influence of DPYD*9A, DPYD*6 and GSTP1 ile105val Genetic Polymorphisms on Capecitabine and Oxaliplatin (CAPOX) Associated Toxicities in Colorectal Cancer (CRC) Patients

AIM

CAPOX treatment in CRC patients was reported to cause several dose-limiting toxicities, and are found responsible for treatment interruption or even discontinuation. Therefore there is a critical need for identifying the predictive biomarkers for such toxicities to prevent them. The aim of our present study is to find the influence of DPYD*9A, DPYD*6 and GSTP1 ile105val gene polymorphisms on CAPOX treatment-associated toxicities in south Indian patients with CRC.

PATIENTS AND METHODS

We have recruited 145 newly diagnosed and treatment naive CRC patients in the study. Each Patient received a standard treatment schedule of oxaliplatin 130 mg/m2 infusion over 2 hours on day 1 and oral capecitabine 1000mg/m2 in divided doses twice daily for the next 14 days of a 21-day cycle. 5 ml of the venous blood was collected from each patient and genomic DNA extraction and genotyping. The genotyping analysis of the selected genetic polymorphisms was carried out by real-time PCR using TaqMan SNP genotyping assays obtained from applied biosystems.

RESULTS

The major dose-limiting toxicities observed with CAPOX treatment were thrombocytopenia, HFS and PN. DPYD*9A carries were found to be at higher risk for HFS, diarrhoea and thrombocytopenia when compared to patients with wild allele. No significant association was found between DPYD*6, GSTP1 ile105val polymorphisms and CAPOX related toxicities except for thrombocytopenia.

CONCLUSION

A significant association was observed between DPYD*9A polymorphism and CAPOX induced dose-limiting toxicities strengthening its role as a predictive biomarker.

Evaluation of the toxicity of 5-fluorouracil on three digestive enzymes from the view of side effects

Among the side effects of 5-fluorouracil (5-FU), the performance of the gastrointestinal reactions is faster and more obvious than others. In this work, the effects of 5-FU on the activities and conformational structures of the important digestive enzymes including α-amylase, pepsin and trypsin were studied to analyze the mechanism of the gastrointestinal adverse effects causing by 5-FU binding. The results showed that the enzymatic activity of pepsin was obviously reduced by the presence of 5-FU that bound directly to the enzyme activity cavity site. The molecular modeling and fluorescence quenching data indicated that the hydrophobic, polar and hydrogen bonding forces were involved in the ground state complex formation between proteases and 5-FU. In addition, 5-FU changed the tertiary structures of α-amylase, pepsin, and trypsin.

Nucleoside dimers analogs containing floxuridine and thymidine with unnatural linker groups: synthesis and cancer line studies. Part III

Two series of novel fluorinated nucleosides dimers with an unnatural 1,2,3-triazole linkage were synthesized. The obtained molecules were prepared using "click" chemistry approach based on copper(I) catalyzed Huisgen azide-alkyne cycloaddition. It was performed between 3'- and 5'-azido-nucleosides as the azide components, and the 3'-O- and 5'-O-propargyl-nucleosides as the alkyne components. Based on analysis of the ³ J_HH, ³ J_H1'C2 and ³ J_H1'C6 we estimated conformational preferences of sugar part and orientation around glycosidic bond. All described nucleosides dimers analogs were characterized by spectroscopic methods and evaluated for their in vitro cytotoxicity in three human cancer cell lines: cervical (HeLa), oral (KB) and breast (MCF-7).

Emerging targets in cancer drug resistance

Drug resistance is a complex phenomenon that frequently develops as a failure to chemotherapy during cancer treatment. Malignant cells increasingly generate resistance to various chemotherapeutic drugs through distinct mechanisms and pathways. Understanding the molecular mechanisms involved in drug resistance remains an important area of research for identification of precise targets and drug discovery to improve therapeutic outcomes. This review highlights the role of some recent emerging targets and pathways which play critical role in driving drug resistance.

Phase I study of preoperative chemoradiotherapy with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer

The present study designed a novel preoperative chemoradiotherapy (CRT) with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer (LARC). This phase I study evaluated the maximum tolerated dose and recommended dose (RD) of oxaliplatin following irinotecan with S-1. Patients with clinical stage T3 or 4 or involvement of the regional nodes and no evidence of distant metastases were treated with fixed doses of S-1 (80 mg/m²/day) on days 1-5, 8-12, 15-19, 22-27 and 29-33, and irinotecan (40 mg/m²/day) on days 1 and 8, followed by oxaliplatin on days 22 and 29. The dose of oxaliplatin was initially 40 mg/m² (level 1) with a predefined dose escalation schedule. The radiation dose was 1.8 Gy/fraction to a total dose of 45 Gy. A total of 9 patients were enrolled in the present study and 7 patients completely received CRT with this study protocol. The maximum tolerated dose for oxaliplatin was 50 mg/m² (level 2). Three of four patients experienced dose-limiting toxicity (grade 3 diarrhea) in oxaliplatin phase of level 2 dose. The RD of oxaliplatin was 40 mg/m² (level 1 dose). In addition, 2 patients had pathological CR (28.5%). Novel preoperative CRT with sequential oxaliplatin and irinotecan with S-1 for LARC resulted in acceptable toxicity and promising efficacy. However, the RD of oxaliplatin was lower than in previous CRT studies that combined oxaliplatin with S-1. To administer higher oxaliplatin, we have planned a phase I trial of preoperative CRT with sequential oxaliplatin followed by irinotecan with S-1 for LARC.

The Main Metabolites of Fluorouracil + Adriamycin + Cyclophosphamide (FAC) Are Not Major Contributors to FAC Toxicity in H9c2 Cardiac Differentiated Cells

In the clinical practice, the combination of 5-fluorouracil (5-FU) + Adriamycin (also known as doxorubicin, DOX) + cyclophosphamide (CYA) (known as FAC) is used to treat breast cancer. The FAC therapy, however, carries some serious risks, namely potential cardiotoxic effects, although the mechanisms are still unclear. In the present study, the role of the main metabolites regarding FAC-induced cardiotoxicity was assessed at clinical relevant concentrations. Seven-day differentiated H9c2 cells were exposed for 48 h to the main metabolites of FAC, namely the metabolite of 5-FU, α-fluoro-β-alanine (FBAL, 50 or 100 μM), of DOX, doxorubicinol (DOXOL, 0.2 or 1 μM), and of CYA, acrolein (ACRO, 1 or 10 μM), as well as to their combination. The parent drugs (5-FU 50 μM, DOX 1 μM, and CYA 50 μM) were also tested isolated or in combination with the metabolites. Putative cytotoxicity was evaluated through phase contrast microscopy, Hoechst staining, membrane mitochondrial potential, and by two cytotoxicity assays: the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and the neutral red (NR) lysosomal incorporation. The metabolite DOXOL was more toxic than FBAL and ACRO in the MTT and NR assays. When in combination, neither FBAL nor ACRO increased DOXOL-induced cytotoxicity. No nuclear condensation was observed for any of the tested combinations; however, a significant mitochondrial potential depolarization after FBAL 100 μM + DOXOL 1 μM + ACRO 10 μM or FBAL 100 μM + DOXOL 1 μM exposure was seen at 48 h. When tested alone DOX 1 μM was more cytotoxic than all the parent drugs and metabolites in both the cytotoxicity assays performed. These results demonstrated that DOXOL was the most toxic of all the metabolites tested; nonetheless, the metabolites do not seem to be the major contributors to FAC-induced cardiotoxicity in this cardiac model.

Diagnostic and Therapeutic Strategies for Fluoropyrimidine Treatment of Patients Carrying Multiple DPYD Variants

DPYD genotyping prior to fluoropyrimidine treatment is increasingly implemented in clinical care. Without phasing information (i.e., allelic location of variants), current genotype-based dosing guidelines cannot be applied to patients carrying multiple DPYD variants. The primary aim of this study is to examine diagnostic and therapeutic strategies for fluoropyrimidine treatment of patients carrying multiple DPYD variants. A case series of patients carrying multiple DPYD variants is presented. Different genotyping techniques were used to determine phasing information. Phenotyping was performed by dihydropyrimidine dehydrogenase (DPD) enzyme activity measurements. Publicly available databases were queried to explore the frequency and phasing of variants of patients carrying multiple DPYD variants. Four out of seven patients carrying multiple DPYD variants received a full dose of fluoropyrimidines and experienced severe toxicity. Phasing information could be retrieved for four patients. In three patients, variants were located on two different alleles, i.e., in trans. Recommended dose reductions based on the phased genotype differed from the phenotype-derived dose reductions in three out of four cases. Data from publicly available databases show that the frequency of patients carrying multiple DPYD variants is low (< 0.2%), but higher than the frequency of the commonly tested DPYD*13 variant (0.1%). Patients carrying multiple DPYD variants are at high risk of developing severe toxicity. Additional analyses are required to determine the correct dose of fluoropyrimidine treatment. In patients carrying multiple DPYD variants, we recommend that a DPD phenotyping assay be carried out to determine a safe starting dose.

Who Can Perform Adjuvant Chemotherapy Treatment for Gastric Cancer? A Multicenter Retrospective Overview of the Current Status in Korea

Purpose

To investigate the current status of adjuvant chemotherapy (AC) regimens in Korea and the difference in efficacy of AC administered by surgical and medical oncologists in patients with stage II or III gastric cancers.

Materials and Methods

We performed a retrospective observational study among 1,049 patients who underwent curative resection and received AC for stage II and III gastric cancers between February 2012 and December 2013 at 29 tertiary referral university hospitals in Korea. To minimize the influence of potential confounders on selection bias, propensity score matching (PSM) was used based on binary logistic regression analysis. The 3-year disease-free survival (DFS) rates were compared between patients who received AC administered by medical oncologists or surgical oncologists.

Results

Between February 2012 and December 2013 in Korea, the most commonly prescribed AC by medical oncologists was tegafur/gimeracil/oteracil (S-1, 47.72%), followed by capecitabine with oxaliplatin (XELOX, 16.33%). After performing PSM, surgical oncologists (82.74%) completed AC as planned more often than medical oncologists (75.9%), with statistical significance (P=0.036). No difference in the 3-year DFS rates of stage II (P=0.567) or stage III (P=0.545) gastric cancer was found between the medical and surgical oncologist groups.

Conclusions

S-1 monotherapy and XELOX are a main stay of AC, regardless of whether the prescribing physician is a medical or surgical oncologist. The better compliance with AC by surgical oncologists is a valid reason to advocate that surgical oncologists perform the treatment of AC for stage II or III gastric cancers.

Biosolvation Nature of Ionic Liquids: Molecular Dynamics Simulation of Methylated Nucleobases in Hydrated 1-Ethyl-3-methylimidazolium Acetate

Solvation free energies of methylated nucleobases were calculated in pure and hydrated 1-ethyl-3-methylimidazolium acetate, [Emim][Ac], ionic liquid, and pure water using classical molecular dynamics simulations using multistate Bennett's acceptance ratio method. The calculated solvation free energies in pure water were compared with the previous experimental and theoretical findings and found to be in agreement. We observe that the solvation free energy of methylated nucleobases is more in the pure ionic liquid compared to that in the pure water and on changing the mole fraction of water in the ionic liquid, the solvation free energy decreases gradually. Comparing the Coulombic and van der Waals contribution to the solvation free energy, electrostatic contribution is more compared to that of the latter for all nucleobases. To obtain the atomistic details and explain the solvation mechanism, we calculated radial distribution functions (RDFs), spatial distribution functions (SDFs), and stacking angle distribution of cations to the nucleobases. From RDFs and SDFs, we find that the acetate anions of the ionic liquid are forming strong hydrogen bonds with the amine hydrogen atoms of the nucleobases. These hydrogen bonds contribute to the major part of the Coulombic contribution to the solvation free energy. Stacking of cations to the nucleobases is primarily due to the van der Waals contribution to the solvation free energy.

Quantitative Proteomics of TRAMP Mice Combined with Bioinformatics Analysis Reveals That PDGF-B Regulatory Network Plays a Key Role in Prostate Cancer Progression

Transgenic adenocarcinoma of the mouse prostate (TRAMP) mice is a widely used transgenic animal model of prostate cancer (PCa). We performed a label-free quantitative proteomics analysis combined with a bioinformatics analysis on the entire prostate protein extraction from TRAMP mice and compared it with WT littermates. From 2379 total identified proteins, we presented a modest mice prostate reference proteome containing 919 proteins. 61 proteins presented a significant expression difference between two groups. The integrative bioinformatics analysis predicted the overexpression of platelet-derived growth factor B (PDGF-B) in tumor tissues and supports the hypothesis of the PDGF-B signaling network as a key upstream regulator in PCa progression. Furthermore, we demonstrated that Crenolanib, a novel PDGF receptor inhibitor, inhibited PCa cell proliferation in a dose-dependent manner. Finally, we revealed the importance of PDGF-B regulatory network in PCa progression, which will assist us in understanding the role and mechanisms of PDGF-B in promoting cancer growth and provide valuable knowledge for future research on anti-PDGF therapy.

Geographical Variations in the Clinical Management of Colorectal Cancer in Australia: A Systematic Review

Background

In Australia, cancer survival is significantly lower in non-metropolitan compared to metropolitan areas. Our objective was to evaluate the evidence on geographical variations in the clinical management and treatment of colorectal cancer (CRC).

Methods

A systematic review of published and gray literature was conducted. Five databases (CINAHL, PubMed, Embase, ProQuest, and Informit) were searched for articles published in English from 1990 to 2018. Studies were included if they assessed differences in clinical management according to geographical location; focused on CRC patients; and were conducted in Australia. Included studies were critically appraised using a modified Newcastle–Ottawa Scale. PRISMA systematic review reporting methods were applied.

Results

17 articles met inclusion criteria. All were of high (53%) or moderate (47%) quality. The evidence available may suggest that patients in non-metropolitan areas are more likely to experience delays in surgery and are less likely to receive chemotherapy for stage III colon cancer and adjuvant radiotherapy for rectal cancer.

Conclusion

The present review found limited information on clinical management across geographic regions in Australia and the synthesis highlights significant issues both for data collection and reporting at the population level, and for future research in the area of geographic variation. Where geographical disparities exist, these may be due to a combination of patient and system factors reflective of location. It is recommended that population-level data regarding clinical management of CRC be routinely collected to better understand geographical variations and inform future guidelines and policy.

Fluorescence and computational studies of thymidine phosphorylase affinity toward lipidated 5-FU derivatives

Thymidine phosphorylase (TP) is an enzyme that is up-regulated in a wide variety of solid tumors, including breast and colorectal cancers. It is involved in tumor growth and metastasis, for this reason it is one of the key enzyme to be inhibited, in an attempt to prevent tumor proliferation. However, it also plays an active role in cancer treatment, through its contribution in the conversion of the anti-cancer drug 5-fluorouracil (5-FU) to an irreversible inhibitor of thymidylate synthase (TS), responsible of the inhibition of the DNA synthesis. In this work, the intrinsic TP fluorescence has been investigated for the first time and exploited to study TP binding affinity for the unsubstituted 5-FU and for two 5-FU derivatives, designed to expose this molecule on liposomal membranes. These molecules were obtained by functionalizing the nitrogen atom with a chain consisting of six (1) or seven (2) units of glycol, linked to an alkyl moiety of 12 carbon atoms. Derivatives (1) and (2) exhibited an affinity for TP in the micromolar range, 10 times higher than the parent compound, irrespective of the length of the polyoxyethylenic spacer. This high affinity was maintained also when the compounds were anchored in liposomal membranes. Experimental results were supported by molecular dynamics simulations and docking calculations, supporting a feasible application of the designed supramolecular lipid structure in selective targeting of TP, to be potentially used as a drug delivery system or sensor device.

O4 -Alkylated-2-Deoxyuridine Repair by O6 -Alkylguanine DNA Alkyltransferase is Augmented by a C5-Fluorine Modification

Oligonucleotides containing various adducts, including ethyl, benzyl, 4-hydroxybutyl and 7-hydroxyheptyl groups, at the O⁴ atom of 5-fluoro-O⁴ -alkyl-2'-deoxyuridine were prepared by solid-phase synthesis. UV thermal denaturation studies demonstrated that these modifications destabilised the duplex by approximately 10 °C, relative to the control containing 5-fluoro-2'-deoxyuridine. Circular dichroism spectroscopy revealed that these modified duplexes all adopted a B-form DNA structure. O⁶ -Alkylguanine DNA alkyltransferase (AGT) from humans (hAGT) was most efficient at repair of the 5-fluoro-O⁴ -benzyl-2'-deoxyuridine adduct, whereas the thymidine analogue was refractory to repair. The Escherichia coli AGT variant (OGT) was also efficient at removing O⁴ -ethyl and benzyl adducts of 5-fluoro-2-deoxyuridine. Computational assessment of N1-methyl analogues of the O⁴ -alkylated nucleobases revealed that the C5-fluorine modification had an influence on reducing the electron density of the O⁴ -C_α bond, relative to thymine (C5-methyl) and uracil (C5-hydrogen). These results reveal the positive influence of the C5-fluorine atom on the repair of larger O⁴ -alkyl adducts to expand knowledge of the range of substrates able to be repaired by AGT.

Sensitive analysis and pharmacokinetic study of a novel gemcitabine carbamate prodrug and its active metabolite gemcitabine in rats using LC-ESI-MS/MS

FY363 is a new chemical entity of gemcitabine analog, which has been shown to have a significant inhibitory effect on cell proliferation in a variety of tumor cell lines in vitro. As a carbamate derivative, FY363 would be converted to the active metabolite gemcitabine through enzyme action in vivo. In order to clarify the exposure of FY363 prototype and its metabolite gemcitabine in vivo after administration of FY363, a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated to simultaneously determine FY363 and gemcitabine in rat plasma after liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved on a highly stable polar column of Synergi 4u Polar-RP 80A (4 μm, 4.6 × 250 mm) which has a unique ether - phenyl bonded phase. Gradient elution was accomplished with mobile phase system consisting of 5 mM ammonium formate buffer containing 0.1% formic acid and mixed organic solvents containing methanol-acetonitrile (3:2, v/v). Multiple reaction monitoring transitions were performed on triple quadrupole mass spectrometric detection in positive-ion mode with an electrospray ionization source. The calibration curves showed good linearity (r > 0.99) over the established concentration range of 1.0-1000 ng/mL both for FY363 and gemcitabine. The assay was validated to be selective, robust and reproducible. This well validated method was successfully applied to demonstrate the pharmacokinetic behavior and the metabolic transformation of FY363 in rats. Results revealed that about 20% of FY363 were converted into its active metabolite gemcitabine in rats by comparing the exposure of gemcitabine after the FY363 administration with that after direct gemcitabine administration at equimolar dose.

Simultaneous determination of gemcitabine prodrug, gemcitabine and its major metabolite 2', 2'-difluorodeoxyuridine in rat plasma by UFLC-MS/MS

To improve bioavailability and provide resistance to deamination, an array of gemcitabine (dFdC) prodrugs carrying the acyl modifications has been successful in the optimization of pharmacokinetic properties of dFdC, but the reports about 4-N-carbobenzoxy-dFdC (Cbz-dFdC), a dFdC prodrug bearing alkyloxycarbonyl modification, are relatively rare. Notably, in vivo enzymatic hydrolysis was an absolutely essential factor for the activation of these prodrugs, which is correlated with the anti-tumor activity. Therefore, detailed metabolism studies of Cbz-dFdC should be carried out for a more authentic pharmacodynamic evaluation. In order to detect the pharmacokinetic characteristics of Cbz-dFdC, a selective, sensitive and accurate method for the simultaneous determination of Cbz-dFdC, along with dFdC and its major metabolite dFdU in rat plasma was developed and validated using UFLC-MS/MS techniques. Column was at 40 °C for separation using an eluent with acetonitrile and 0.1% formic acid, 1 mM ammonium formate at a flow rate of 0.2 mL/min. Detection was performed using ESI source in positive ion selected reaction monitoring mode by monitoring the following ion transitions m/z 398.1 → 202.2 (Cbz-dFdC), m/z 264.1 → 112.0 (dFdC), m/z 265.3 → 113.2 (dFdU) and m/z 246.1 → 112.0 (IS). Analytes were extracted by simple precipitation with acetonitrile containing internal standards followed by liquid-liquid extraction with ethyl acetate. The calibration curves of Cbz-dFdC, dFdC and dFdU were linear in the concentration range of 2 to 500 ng/mL, 2 to 500 ng/mL and 40 to 10,000 ng/mL, respectively. The assay ranges selected for the three analytes were appropriate and minimized the need for reanalysis. All the validation data, such as intra- and inter-day precision, accuracy, selectivity and stability, were within the required limits. In conclusion, the sensitive analytical assay was selective and accurate for the determination of rat plasma concentrations of Cbz-dFdC, dFdC and dFdU from a single LC-MS/MS analysis and well-suited to support pharmacokinetic studies.

Correlation of Expression Levels of Copper Transporter 1 and Thymidylate Synthase with Treatment Outcomes in Patients with Advanced Non-small Cell Lung Cancer Treated with S-1/Carboplatin Doublet Chemotherapy

Background: Copper transporter 1 (CTR1) is a critical determinant of the uptake and cytotoxic effect of the platinum drugs carboplatin and cisplatin. Thymidylate synthase (TS) is an enzyme involved in DNA synthesis and is associated with resistance of tumor cells to 5-fluorouracil. We investigated the correlation between CTR1 and TS expression levels and treatment outcomes in patients with advanced non-small-cell lung cancer (NSCLC) treated with S-1/carboplatin doublet chemotherapy. Methods: Twenty-nine patients were enrolled in this study. Tumor expression of CTR1 and TS was measured immunohistochemically and analyzed for correlation with tumor response, progression-free survival (PFS), and overall survival (OS). Results: Tumor response was significantly better in patients with CTR1High tumors than in patients with CTR1Low tumors (64% vs. 18%, P = 0.02). Patients with TSLow tumors had a significantly longer OS (median 21.2 vs. 8.5 months, P = 0.02), but not PFS, than patients with TSHigh tumors. When CTR1 and TS co-expression was analyzed, patients with either CTR1High or TSLow tumors showed a significantly better tumor response (50% vs. 0%, P = 0.01), longer PFS (median 4.2 vs. 2.1 months, P = 0.03), and longer OS (median 21.2 vs. 8.5 months, P = 0.01) than patients with both CTR1Low and TSHigh tumors. Conclusions: Our study suggests that combined CTR1/TS expression status has the potential to be an important predictor of good treatment outcomes in patients with advanced NSCLC treated with S-1/carboplatin doublet chemotherapy.

Loss of Uracil DNA Glycosylase Selectively Resensitizes p53-Mutant and -Deficient Cells to 5-FdU

Thymidylate synthase (TS) inhibitors including fluoropyrimidines [e.g., 5-Fluorouracil (5-FU) and 5-Fluorodeoxyuridine (5-FdU, floxuridine)] and antifolates (e.g., pemetrexed) are widely used against solid tumors. Previously, we reported that shRNA-mediated knockdown (KD) of uracil DNA glycosylase (UDG) sensitized cancer cells to 5-FdU. Because p53 has also been shown as a critical determinant of the sensitivity to TS inhibitors, we further interrogated 5-FdU cytotoxicity after UDG depletion with regard to p53 status. By analyzing a panel of human cancer cells with known p53 status, it was determined that p53-mutated or -deficient cells are highly resistant to 5-FdU. UDG depletion resensitizes 5-FdU in p53-mutant and -deficient cells, whereas p53 wild-type (WT) cells are not affected under similar conditions. Utilizing paired HCT116 p53 WT and p53 knockout (KO) cells, it was shown that loss of p53 improves cell survival after 5-FdU, and UDG depletion only significantly sensitizes p53 KO cells. This sensitization can also be recapitulated by UDG depletion in cells with p53 KD by shRNAs. In addition, sensitization is also observed with pemetrexed in p53 KO cells, but not with 5-FU, most likely due to RNA incorporation. Importantly, in p53 WT cells, the apoptosis pathway induced by 5-FdU is activated independent of UDG status. However, in p53 KO cells, apoptosis is compromised in UDG-expressing cells, but dramatically elevated in UDG-depleted cells. Collectively, these results provide evidence that loss of UDG catalyzes significant cell death signals only in cancer cells mutant or deficient in p53.Implications: This study reveals that UDG depletion restores sensitivity to TS inhibitors and has chemotherapeutic potential in the context of mutant or deficient p53. Mol Cancer Res; 16(2); 212-21. ©2017 AACR.

Inhibition of uracil DNA glycosylase sensitizes cancer cells to 5-fluorodeoxyuridine through replication fork collapse-induced DNA damage

5-fluorodeoxyuridine (5-FdU, floxuridine) is active against multiple cancers through the inhibition of thymidylate synthase, which consequently introduces uracil and 5-FU incorporation into the genome. Uracil DNA glycosylase (UDG) is one of the main enzymes responsible for the removal of uracil and 5-FU. However, how exactly UDG mediates cellular sensitivity to 5-FdU, and if so whether it is through its ability to remove uracil and 5-FU have not been well characterized. In this study, we report that UDG depletion led to incorporation of uracil and 5-FU in DNA following 5-FdU treatment and significantly enhanced 5-FdU's cytotoxicity in cancer cell lines. Co-treatment, but not post-treatment with thymidine prevented cell death of UDG depleted cells by 5-FdU, indicating that the enhanced cytotoxicity is due to the retention of uracil and 5-FU in genomic DNA in the absence of UDG. Furthermore, UDG depleted cells were arrested at late G1 and early S phase by 5-FdU, followed by accumulation of sub-G1 population indicating cell death. Mechanistically, 5-FdU dramatically reduced DNA replication speed in UDG depleted cells. UDG depletion also greatly enhanced DNA damage as shown by γH2AX foci formation. Notably, the increased γH2AX foci formation was not suppressed by caspase inhibitor treatment, suggesting that DNA damage precedes cell death induced by 5-FdU. Together, these data provide novel mechanistic insights into the roles of UDG in DNA replication, damage repair, and cell death in response to 5-FdU and suggest that UDG is a target for improving the anticancer effect of this agent.

An Inhalable Powder Formulation Based on Micro- and Nanoparticles Containing 5-Fluorouracil for the Treatment of Metastatic Melanoma

Melanoma is the most aggressive and lethal type of skin cancer, with a poor prognosis because of the potential for metastatic spread. The aim was to develop innovative powder formulations for the treatment of metastatic melanoma based on micro- and nanocarriers containing 5-fluorouracil (5FU) for pulmonary administration, aiming at local and systemic action. Therefore, two innovative inhalable powder formulations were produced by spray-drying using chondroitin sulfate as a structuring polymer: (a) 5FU nanoparticles obtained by piezoelectric atomization (5FU-NS) and (b) 5FU microparticles of the mucoadhesive agent Methocel™ F4M for sustained release produced by conventional spray drying (5FU-MS). The physicochemical and aerodynamic were evaluated in vitro for both systems, proving to be attractive for pulmonary delivery. The theoretical aerodynamic diameters obtained were 0.322 ± 0.07 µm (5FU-NS) and 1.138 ± 0.54 µm (5FU-MS). The fraction of respirable particles (FR%) were 76.84 ± 0.07% (5FU-NS) and 55.01 ± 2.91% (5FU-MS). The in vitro mucoadhesive properties exhibited significant adhesion efficiency in the presence of Methocel™ F4M. 5FU-MS and 5FU-NS were tested for their cytotoxic action on melanoma cancer cells (A2058 and A375) and both showed a cytotoxic effect similar to 5FU pure at concentrations of 4.3 and 1.7-fold lower, respectively.

Overexpression of Smac/DIABLO in Hep-2 Cell Line: Possible Role in Potentiating the Sensitivity of Chemotherapeutic Drugs

Aims and background

The major obstacles for tumor chemotherapy are drug resistance and/or adverse effects on the host. In the present study we investigated the role of the second mitochondria-derived activator of caspase (Smac/DIABLO) in the action of cisplatin (DDP), 5-fluorouracil (5-FU), and the combination of both in Hep-2 cells.

Methods and study design

Hep-2 laryngeal carcinoma cells exposed to DDP, 5-FU and the combination of both were investigated. Cell viability was determined by MTT assay. Apoptosis was measured by Ho.33342 and PI double staining and flow cytometry. The expression of Smac/DIABLO at the mRNA and protein level was assayed by RT-PCR and Western blotting.

Results

DDP, 5-FU and the combination of both drugs reduced the cell survival rates in a concentration- and time-dependent manner. The drug combination not only exerted a stronger inhibitory effect, but also at a lower concentration compared with the single drugs. Apoptosis was concomitant in a caspase-dependent manner. The expression of Smac/DIABLO increased significantly at both mRNA and protein levels after cell exposure to the combination compared with single drugs.

Conclusions

Smac/DIABLO plays a pivotal role in attaining a synergistic effect in Hep-2 cells in response to this combined strategy.

Nucleobase deaminases: a potential enzyme system for new therapies

This review presents an overview of the structure, function and mechanism of CDA deaminases and their potential as enzyme systems for development of new antimicrobial therapies.

Pharmacogenetic landscape of DPYD variants in south Asian populations by integration of genome-scale data

AIM

Adverse drug reactions to 5-Fluorouracil(5-FU) is frequent and largely attributable to genetic variations in the DPYD gene, a rate limiting enzyme that clears 5-FU. The study aims at understanding the pharmacogenetic landscape of DPYD variants in south Asian populations.

MATERIALS & METHODS

Systematic analysis of population scale genome wide datasets of over 3000 south Asians was performed. Independent evaluation was performed in a small cohort of patients.

RESULTS

Our analysis revealed significant differences in the the allelic distribution of variants in different ethnicities.

CONCLUSIONS

This is the first and largest genetic map the DPYD variants associated with adverse drug reaction to 5-FU in south Asian population. Our study highlights ethnic differences in allelic frequencies.

Reversible severe fatty liver induced by capecitabine: A case report

RATIONALE

Capecitabine (CAP) is a chemotherapeutic agent used to treat breast and gastrointestinal cancers. The most common adverse reactions of CAP primarily included gastrointestinal and dermatological effects. Whereas, the CAP-induced fatty liver had never been reported.

PATIENT CONCERNS

In this study, a-69-year old female presented a history of hypertension with regulated blood pressure, whereas diabetes mellitus, hyperlipidemia, and hepatitis were excluded. No alcohol,tobacco, or other drugs use was declared.

DIAGNOSES

She was diagnosed as infiltrating ductal carcinoma of left breast with the hepatic and pulmonary metastasis. The dihydropyrimidine dehydrogenase (DPD) deficiency is not involved.

INTERVENTIONS

She received treatment with CAP that was administered orally at a dosage of 1500mg twice daily intermittently (2weeks on/1 week off). The treatment was well-tolerated any typical adverse reactions such as diarrhea, nausea, and hand-foot syndrome (HFS) were noted. The parameters of the functional liver, the total cholesterol, and triglyceride were in normal ranges before and after therapy. After 3 cycles of the treatment, computed tomography (CT) scan revealed signs of fatty liver. After a 10-cycle course, CAP was substituted with tamoxifen because of the further aggravation of fatty liver.

OUTCOMES

Several months after withdrawal, the follow-up CT scans demonstrated significant improvement of fatty liver.

LESSONS

We presented a case of breast cancer with severe fatty liver as a consequence of the administration of CAP that was not involved in DPD deficiency or CAP-associated hypertriglyceridemia; these potential adverse effects of therapy with CAP should be intensely investigated.

Synergistic antitumor activity of a self-assembling camptothecin and capecitabine hybrid prodrug for improved efficacy

The direct use of anticancer drugs to create their own nanostructures is an emerging concept in the field of drug delivery to obtain nanomedicines of high drug loading and high reproducibility, and the combination use of two or more drugs has been a proven clinical strategy to enhance therapeutic outcomes. We report here the synthesis, assembly and cytotoxicity evaluation of self-assembling hybrid prodrugs containing both camptothecin (CPT) and a capecitabine (Cap) analogue. CPT and Cap molecules were conjugated onto a short β-sheet-forming peptide (Sup35) to yield three different self-assembling prodrugs (dCPT-Sup35, CPT-Cap-Sup35 and dCap-Sup35). We found that the chemical structure of conjugated drugs could strongly influence their assembled morphology as well as their structural stability in aqueous solution. With a decrease in number of CPT units, the resulting nanostructures exhibited a morphological transformation from nanofibers (dCPT-Sup35) to filaments (CPT-Cap-Sup35) then to spherical particles (dCap-Sup35). Notably, the hybrid CPT-Cap prodrug showed a synergistic effect and significantly enhanced potency against three esophageal adenocarcinoma cell lines compared with the two homo-prodrugs (dCPT-Sup35 and dCap-Sup35) as well as free parent drugs (CPT, 5-Fu and CPT/5-FU mixture (1:1)). We believe this work represents a conceptual advancement in integrating two structurally distinct drugs of different action mechanisms into a single self-assembling hybrid prodrug to construct self-deliverable nanomedicines for more effective combination chemotherapy.