Dihydropyrimidine Dehydrogenase Polymorphism c.2194G>A Screening Is a Useful Tool for Decreasing Gastrointestinal and Hematological Adverse Drug Reaction Risk in Fluoropyrimidine-Treated Patients.

Although the risk of fluoropyrimidine toxicity may be decreased by identifying poor metabolizers with a preemptive dihydropyrimidine dehydrogenase (DPYD) test, following international standards, many patients with wild-type (WT) genotypes for classic variations may still exhibit adverse drug reactions (ADRs). Therefore, the safety of fluoropyrimidine therapy could be improved by identifying new DPYD polymorphisms associated with ADRs. This study was carried out to assess whether testing for the underestimated c.2194G>A (DPYD*6 polymorphism, rs1801160) is useful, in addition to other well-known variants, in reducing the risk of ADRs in patients undergoing chemotherapy treatment. This retrospective study included 132 patients treated with fluoropyrimidine-containing regimens who experienced ADRs such as gastrointestinal, dermatological, hematological, and neurological. All subjects were screened for DPYD variants DPYD2A (IVS14+1G>A, c.1905+1G>A, rs3918290), DPYD13 (c.1679T>G, rs55886062), c.2846A>T (rs67376798), c.1236G>A (rs56038477), and c.2194G>A by real-time polymerase chain reaction (RT-PCR). In this cohort, the heterozygous c.2194G>A variant was present in 26 patients, while 106 individuals were WT; both subgroups were compared for the incidence of ADRs. This assessment revealed a high incidence of gastrointestinal and hematological ADRs in DPYD6 carriers compared to WT. Moreover, we have shown a higher prevalence of ADRs in females compared to males when stratifying c.2194G>A carrier individuals. Considering that c.2194G>A was linked to clinically relevant ADRs, we suggest that this variant should also be assessed preventively to reduce the risk of fluoropyrimidine-related ADRs.

HPMC-Zein Film-forming Gel Loaded with 5-Fluorouracil Coupled with CO2 Laser Dermabrasion for Managing Stable Vitiligo.

Vitiligo is a significant dermatological challenge affecting 0.5 to 2% of the global population. Despite the various existing medical approaches, current vitiligo treatments are far from ideal. The present study aimed to prepare and evaluate a film-forming gel of 5 fluorouracil (5FU) using different ratios of hydroxypropyl methylcellulose (HPMC) and Zein for treating vitiligo. The prepared film-forming gels were fully characterized in terms of morphology, Fourier-transform infrared spectroscopy, drug content, pH, drying time, in-vitro drug release, and clinical investigation. A 32-full factorial design was used to study the impact of varying concentrations of HPMC (X1) and Zein (X2) on the percentage of 5FU released (Y1) from the prepared film-forming gels. Scanning electron microscopy (SEM) revealed a cross-linked network structure between polymers. An increase in HPMC concentration (2-4%) correlated with higher 5FU release, whereas increased Zein concentration (1-2%) resulted in reduced 5FU release. Furthermore, patients treated with 5FU film-forming gel after dermabrasion with fractional CO2 (FCO2) laser exhibited a significant decrease in JAK3 gene expression and higher effectiveness than those treated with FCO2 laser alone. Our results suggest that the film-forming gel of 5FU is promising as an effective formulation for treating vitiligo.

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

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

Colorectal Cancer Bioengineered Microtissues as a Model to Replicate Tumor-ECM Crosstalk and Assess Drug Delivery Systems In Vitro.

Current 3D cancer models (in vitro) fail to reproduce complex cancer cell extracellular matrices (ECMs) and the interrelationships occurring (in vivo) in the tumor microenvironment (TME). Herein, we propose 3D in vitro colorectal cancer microtissues (3D CRC µTs), which reproduce the TME more faithfully in vitro. Normal human fibroblasts were seeded onto porous biodegradable gelatin microbeads (GPMs) and were continuously induced to synthesize and assemble their own ECMs (3D Stroma µTs) in a spinner flask bioreactor. Then, human colon cancer cells were dynamically seeded onto the 3D Stroma µTs to achieve the 3D CRC µTs. Morphological characterization of the 3D CRC µTs was performed to assess the presence of different complex macromolecular components that feature in vivo in the ECM. The results showed the 3D CRC µTs recapitulated the TME in terms of ECM remodeling, cell growth, and the activation of normal fibroblasts toward an activated phenotype. Then, the microtissues were assessed as a drug screening platform by evaluating the effect of 5-Fluorouracil (5-FU), curcumin-loaded nanoemulsions (CT-NE-Curc), and the combination of the two. When taken together, the results showed that our microtissues are promising in that they can help clarify complex cancer-ECM interactions and evaluate the efficacy of therapies. Moreover, they may be combined with tissue-on-chip technologies aimed at addressing further studies in cancer progression and drug discovery.

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.

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.

Ultrasensitive and Specific Detection of Anticancer Drug 5-Fluorouracil in Blood Samples by a Surface-Enhanced Raman Scattering (SERS)-Based Lateral Flow Immunochromatographic Assay.

5-Fluorouracil (5-FU) is an effective anticancer drug widely used in the world. To improve therapy efficiency and reduce side effects, it is very important to frequently detect the concentration of 5-FU in blood samples of patients. In this work, a new type of lateral flow immunochromatographic assay (LFIA) based on surface-enhanced Raman scattering (SERS) for ultrasensitive and specific detection of 5-FU in blood samples was developed. Au@Ag/Au nanoparticles (NPs) employing Au particles as the core and Ag/Au alloy as the shell were synthesized, characterized and used as the substrate in SERS-LFIA due to their high SERS enhancement and biocompatibility. The immunoprobe was made in the form of AuMBA@Ag/Au-Ab in which mercaptobenzoic acid (MBA, a common Raman active reporter) was embedded in the core-shell layer and the monoclonal antibody (mAb) against 5-FU was immobilized on the surface. The performance of SERS-LFIA was similar to that in colloidal gold based-LFIA, and the entire assay time was within 20 min. According to the color intensity on the testing (T) lines of LFIA strips visualized by eyes, the contents of 5-FU in the samples could be qualitatively or semi-quantitatively identified. Furthermore, by measuring the characteristic Raman intensities of MBA on T lines, quantitative detection of 5-FU in the samples were achieved. The IC50 and limit of detection (LOD) of the LFIA for 5-FU were found to be 20.9 pg mL-1 and 4.4 pg mL-1, respectively. There was no cross-reactivity (CR) of the LFIA with nine relative compounds, and the CR with cytosine, tegafur and carmofur were less than 4.5%. The recoveries of 5-FU from spiked blood samples were in the range of 78.6~86.4% with the relative standard deviation (RSD) of 2.69~4.42%. Five blood samples containing 5-FU collected from the Cancer Hospital were measured by SERS-LFIA, and the results were confirmed by LC-MS/MS. It was proven that the proposed method was able to simply and rapidly detect 5-FU in blood samples with high sensitivity, specificity, accuracy and precision.

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, ZHER2:2891, 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 ZHER2:2891 and fused with those of ABD (albumin-binding domain) and Fcy. The purified ZHER2:2891-ABD-Fcy fusion protein specifically binds to HER2 with a Kd value of 1.6 nM ZHER2:2891-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 ZHER2:2891-ABD-Fcy in the presence of 5-FC, and the IC50 values of ZHER2:2891-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, ZHER2:2891-ABD-Fcy/5-FC, might become a promising addition to the existing class of therapeutics specifically target HER2-expressing cancers.

Elucidation of underlying molecular mechanism of 5-Fluorouracil chemoresistance and its restoration using fish oil in experimental colon carcinoma.

Latest strategies for cancer treatment primarily focus on the use of chemosensitizers to enhance therapeutic outcome. N-3 PUFAs have emerged as the strongest candidate for the prevention of colorectal cancer (CRC). Our previous studies have demonstrated that fish oil (FO) rich in n-3 PUFAs not only increased therapeutic potential of 5-Fluorouracil(5-FU) in colon cancer but also ameliorated its toxicity. Henceforth, the present study is designed to elucidate mechanistic insights of FO as a chemosensitizer to circumvent drug resistance in experimental colon carcinoma. The colon cancer was induced by 1,2-dimethylhydrazine(DMH)/dextran sulfate sodium(DSS) in male Balb/c mice and these animals were treated with 5-FU(12.5 mg/kg b.w.), FO(0.2 ml), or 5-FU + FO(12.5 mg/kg b.w + 0.2 ml) orally for 14 days. The molecular mechanism of overcoming 5-FU resistance using FO in colon cancer was delineated by estimating expression of cancer stem cell markers using flowcytometric method and drug transporters by immunohistochemistry and immunoblotting. Additionally, distribution profile of 5-FU and its cytotoxic metabolite, 5-FdUMP at target(colon), and non-target sites (serum, kidney, liver, spleen) was assessed using high-performance liquid chromatography(HPLC) method. The observations revealed that expression of CSCs markers was remarkably reduced after using fish oil along with 5-FU in carcinogen-treated animals. Interestingly, the use of FO alongwith 5-FU also significantly declined the expression of drug transporters (ABCB1,ABCC5) and consequently resulted in an increased cellular uptake of 5-FU and its metabolite, 5-FdUMP at target site (colon). It could be possibly associated with change in permeability of cell membrane owing to the alteration in membrane fluidity. The present study revealed the mechanistic insights of FO as a MDR revertant which successfully restored 5-FU-mediated chemoresistance in experimental colon carcinoma.

Effects of 10.6-µm laser moxibustion and electroacupuncture at ST36 in a 5-Fu-induced diarrhea rat model.

OBJECTIVE: The aim of this study was to investigate the effect of 10.6-µm laser moxibustion and electroacupuncture in 5-fluorouracil (5-Fu)-induced diarrhea model rats. METHODS: Forty-eight Sprague Dawley rats were randomly divided into 4 groups: a normal group, model group, 10.6-µm laser moxibustion (LM) group, and electroacupuncture (EA) group. Diarrhea was induced by 5-Fu (50 mg/kg) injection in 36 rats; the LM and EA groups received treatment at acupoint ST36 (Zusanli) on hind limbs once a day for 6 days. RESULTS: 5-Fu injection caused body weight decline and diarrhea. From the 5th to 7th day, the LM group showed higher body weights than the model group (P < 0.05). On the 6th day, diarrhea score of the LM group was better than that of the EA group (P < 0.05). Both scores of the LM group and EA group were better than that of model group (P < 0.05). The LM group and EA group both had better intestine pathological scores and lower endotoxin (ET) and diamine oxide (DAO) activity than the model group (P < 0.01). The LM group got better pathological scores than the EA group (P < 0.01). Ultramicroscopic structures of the model group showed severe damage while the LM group and EA group remained good in their small intestines. The model group had obviously decreased occludin protein in intestine tissues than the control group (P < 0.01), while occludin expressions in the LM group and EA group were both obviously increased compared with the model group (P < 0.01). CONCLUSION: LM and EA treatment on ST36 could alleviate damage to intestinal barrier function and alleviate diarrhea caused by 5-Fu.

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.

[Curcumin mediates IL-6/STAT3 signaling pathway to repair intestinal mucosal injury induced by 5-FU chemotherapy for colon cancer].

This study aims to investigate the potential mechanism of curcumin in mediating interleukin-6(IL-6)/signal transducer and activator of transcription 3(STAT3) signaling pathway to repair intestinal mucosal injury induced by 5-fluorouracil(5-FU) chemotherapy for colon cancer. SD rats were intraperitoneally injected with 60 mg·kg~(-1)·d~(-1) 5-FU for 4 days to establish a model of intestinal mucosal injury. Then the rats were randomly divided into model group(equal volume of normal saline), curcumin low, medium and high dose groups(50, 100, 200 mg·kg~(-1)), and normal SD rats were used as control group(equal volume of normal saline). Each group received gavage administration for 4 consecutive days, and the changes of body weight and feces were recorded every day. After administration, blood was collected from the heart, and jejunum tissues were collected. The levels of serum interleukin-1ß(IL-1ß) and tumor necrosis factor-α(TNF-α) were detected by ELISA, and at the same time, the concentration of Evans blue(EB) in jejunum was measured. Hematoxylin-eosin(HE) staining was used to observe the pathological state of jejunum, and the length of jejunum villi and the depth of crypt were measured. The positive expression levels of claudin, occludin and ZO-1 were detected by immunohistochemistry. Western blot was used to detect the protein expression of IL-6, p-STAT3, E-cadherin, vimentin and N-cadherin in jejunum tissues. The results showed that, curcumin significantly increased body weight and fecal weight(P<0.05 or P<0.01), decreased fecal score, EB concentration, IL-1ß and TNF-α levels(P<0.05 or P<0.01) in rats. In addition, curcumin maintained the integrity of mucosal surface and villi structure of jejunum to a large extent, and reduced pathological changes in a dose-dependent manner. Meanwhile, curcumin could increase the positive expression of occludin, claudin and ZO-1(P<0.05 or P<0.01), repair intestinal barrier function, downregulate the protein expression of IL-6, p-STAT3, vimentin and N-cadherin in jejunum tissues(P<0.05 or P<0.01), and upregulate the protein expression of E-cadherin(P<0.05). Therefore, curcumin could repair the intestinal mucosal injury induced by 5-FU chemotherapy for colon cancer, and the mechanism may be related to the inhibition of IL-6/STAT3 signal and the inhibition of epithelial-mesenchymal transition(EMT) process.

Colon-specific tablets containing 5-fluorouracil microsponges for colon cancer targeting.

Most anticancer medications undergo major first-pass metabolism in the intestinal wall, the liver, or both. 5-fluorouracil (5-FU) is known to have erratic oral bioavailability due to first-pass metabolism. The present study aimed to develop 5-FU-loaded microsponges (MS) compressed in enteric-coated tablets as a new colon targeting to colorectal cancer. MS was prepared as a controlled release system for 5-FU and characterized for drug encapsulation efficiency, and surface morphology. Further, hydroxypropyl methylcellulose (HPMC) was mixed with pectin and characterized for their flow as a tablet coat enclosing the core tablets of 5-FU-MS. Moreover, in vitro drug release behavior was studied in different pH media, while the X-ray imaging was used to monitor the in vivo movement of prepared tablets containing 5-FU-MS throughout the GI system. The results showed that MS were spherical in shape and have several pores on their surfaces. The encapsulation efficiency was from 71.80 ± 1.62% - 101.3 ± 2.60%, while the particle size was from 53.11 ± 41.03 - 118.12 ± 48.21 nm. The formulated tablets were fulfilling all official and other specifications and exhibited sustained release of 5-FU only inside the colon. The in vivo human volunteer study of X-ray has shown that the tablets ultimately reached the colon without disturbing in the upper GI system. The obtained carrier formulation is considered as a novel system to deliver 5-FU to the colon tumor with 100% targeting without any drug release in the upper GIT or first-pass metabolism.

[Study on synergistic anti-tumor effect of Shuangdan Capsules combined with 5-FU on hepatocellular carcinoma cells Huh-7 and xenograft mice].

This paper discussed the synergistic anti-tumor effect of Shuangdan Capsules combined with 5-fluorouracil(5-FU) on human liver cancer cell line Huh-7 and tumor bearing mice. The effects of Shuangdan Capsules combined with 5-FU on the activity and vascular endothelial growth factor(VEGF) receptor protein expression of Huh-7 cells were investigated, and the effects of drug combination on tube formation of HUVEC cell were also verified. In addition, the mice model of Huh-7 was established to observe the anti-tumor effect of drug combination and the distribution of tumor blood flow in tumor bearing mice by using molecular imaging. HPLC analysis showed that Shuangdan Capsules mainly consisted of danshensusodium, protocatechuic aldehyde, paeoniflorin, rosmarinic acid, alkannic acid, salvianolic acid B, and paeonol. In MTT experiment, the inhibition rate of Shuangdan Capsules(20 mg·L~(-1)) and 5-FU(1 µmol·L~(-1)) on Huh-7 cells was 60%, and the CI value was 0.59, suggesting that these two drugs had synergistic anti-hepatoma cells effect. The expression of VEGF receptor in Huh-7 cells was inhibited by the combination of these two drugs. In addition, the process of HUVEC was slow, and the number, length and area of the lumen branches decreased significantly. In vivo, Shuangdan Capsules combined with 5-FU inhibited the growth and prolongation of survival of Huh-7 cells in subcutaneous transplanted tumor nude mice; serum expression of CD31 and VEGF in nude mice were decreased, while caspase-3 was increased. Meanwhile, the drug combination significantly inhibited the expressions of MMP2 and VEGF in tumor tissues. Ultrasound showed that Shuangdan Capsules combined with 5-FU also inhibited tumor angiogenesis and reduced blood flow of tumor tissue. The results showed that Shuangdan Capsules combined with 5-FU may inhibit tumor angiogenesis by inhibiting VEGF and MMP2 expressions, thereby blocking tumor growth.

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.

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.

Contribution of oxidative stress in acute intestinal mucositis induced by 5 fluorouracil (5-FU) and its pro-drug capecitabine in rats.

This study was designed to examine the contribution of oxidative stress in gastrointestinal disorders after an intraperitoneal administration of 5 fluorouracil (5-FU; 100 mg/kg of body weight (b.w.)) and capecitabine oral administration (500 mg/kg b.w.). The animals were divided into three groups: Group A (NaCl,10 ml/kg of b.w.) considered as control group, group B was intoxicated by 5-FU and group C was the group of animals treated with capecitabine (CAP). To evaluate the secretory and enteropooling effects, we used magnesium sulfate (MgSO4), 1 ml/100 g of b.w. as a hypersecretion agent . The mucosal gastro-intestinal specimens were scraped and examined for biological markers of oxidative stress and intracellular mediators. These anticancer drugs caused many intestinal damages manifested by an elevation of fluid accumulation and imbalance in electrolytes secretion. The intestinal tissues from treated rats not only showed a significant increase in malondialdehyde (MDA), protein carbonylation and hydrogen peroxide (H2O2) production. but also showed a significant depletion of enzymatic and non-enzymatic antioxidant, such as, glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) and sulfhydryl groups (-SH). These effects were related with histopathological damage and a perturbation of intracellular mediators. As expected, these disturbances were observed in the group of rats poisoned by the MgSO4. Data suggest the contribution of oxidative stress in chemotherapy-induced many disorders in intestinal tract.

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.

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.