Fluorouracil and the new oral fluorinated pyrimidines

Synthesis and cytotoxicity of novel 6,8,9-trisubstituted purine analogs against liver cancer cells

A series of novel 6-(substituted phenyl piperazine)-8-(4-substituted phenyl)-9-cyclopentyl purines, 10-51, were synthesized by a four-step synthesis, achieving an overall yield of about 43 %. The reaction conditions were effectively optimized, and the final products were obtained with high purity and yield in all synthesis steps. The synthesized nucleobases were evaluated for their in vitro cytotoxic activities on selected human cancer cell lines (HUH7 (liver), HCT116 (colon), and MCF7 (breast)) using the Sulforhodamine B (SRB) assay. Among these analogs, compounds bearing 4-trifluoromethyl phenyl (19, 20 and 21), 4-methoxy phenyl (27) and 4-fluoro phenyl (34) substitutions at C-8 of purine were the most potent, and they were also analyzed in drug-resistance and drug-sensitive hepatocellular cancer cell (HCC) panels. Compound 19 displayed remarkable anticancer activities (IC50 = 2.9-9.3 μM) against Huh7, FOCUS, SNU475, SNU182, HepG2, and Hep3B cells compared to the positive control, Fludarabine. Additionally, the pharmacological properties and toxicity profiles of the molecules were investigated computationally by the Swiss-ADME and Pro-Tox II online tools, respectively. Results showed that our compounds have favorable physicochemical characteristics for oral bioavailability and do not reveal any toxicity endpoints such as carcinogenicity, immunotoxicity, mutagenicity, or cytotoxicity.

PROTAC'ing oncoproteins: targeted protein degradation for cancer therapy

Molecularly targeted cancer therapies substantially improve patient outcomes, although the durability of their effectiveness can be limited. Resistance to these therapies is often related to adaptive changes in the target oncoprotein which reduce binding affinity. The arsenal of targeted cancer therapies, moreover, lacks coverage of several notorious oncoproteins with challenging features for inhibitor development. Degraders are a relatively new therapeutic modality which deplete the target protein by hijacking the cellular protein destruction machinery. Degraders offer several advantages for cancer therapy including resiliency to acquired mutations in the target protein, enhanced selectivity, lower dosing requirements, and the potential to abrogate oncogenic transcription factors and scaffolding proteins. Herein, we review the development of proteolysis targeting chimeras (PROTACs) for selected cancer therapy targets and their reported biological activities. The medicinal chemistry of PROTAC design has been a challenging area of active research, but the recent advances in the field will usher in an era of rational degrader design.

Bio- and Hemo-Compatible Silk Fibroin PEGylated Nanocarriers for 5-Fluorouracil Chemotherapy in Colorectal Cancer: In Vitro Studies

5-fluorouracil (5-FU) remains the gold standard of treatment for colorectal cancer, but its poor bioavailability and high systemic toxicity highlight the urgent need for the development of novel delivery strategies to increase the efficacy of 5-FU treatment. The present study is aimed to design and validate a PEGylated Silk Fibroin Nanocarrier (SF/PEG nanoparticles (NPs)) as an efficient 5-FU delivery system for potential intravenous administration. Using the human adenocarcinoma HT–29 cell line as an in vitro model for colorectal cancer, the cytotoxicity screening of the SF/PEG NPs showed that pristine nanocarriers were highly biocompatible, while the addition of 5-FU triggers a dramatic reduction in tumor cell viability, proliferation potential and mitochondrial integrity as well as a significant increase in nitric oxide production. Despite their high in vitro cytotoxicity, the 5-FU SF/PEG NPs were found hemocompatible as no impact on red blood cells hemolysis or the phagocytic activity of the granulocytes was observed. Exposure of HT–29 tumor cells and blood samples to 5-FU SF/PEG NPs augmented the tumor necrosis factor-α levels. Moreover, 5-FU SF/PEG NPs showed an impact on tumor cell migration and invasive potential as both of these processes were inhibited by the NP treatment.

Implementing DPYD*2A Genotyping in Clinical Practice: The Quebec, Canada, Experience

BACKGROUND

Fluoropyrimidines are used in chemotherapy combinations for multiple cancers. Deficient dihydropyrimidine dehydrogenase activity can lead to severe life-threatening toxicities. DPYD*2A polymorphism is one of the most studied variants. The study objective was to document the impact of implementing this test in routine clinical practice.

METHODS

We retrospectively performed chart reviews of all patients who tested positive for a heterozygous or homozygous DPYD*2A mutation in samples obtained from patients throughout the province of Quebec, Canada.

RESULTS

During a period of 17 months, 2,617 patients were tested: 25 patients tested positive. All were White. Twenty-four of the 25 patients were heterozygous (0.92%), and one was homozygous (0.038%). Data were available for 20 patients: 15 were tested upfront, whereas five were identified after severe toxicities. Of the five patients confirmed after toxicities, all had grade 4 cytopenias, 80% grade ≥3 mucositis, 20% grade 3 rash, and 20% grade 3 diarrhea. Eight patients identified with DPYD*2A mutation prior to treatment received fluoropyrimidine-based chemotherapy at reduced initial doses. The average fluoropyrimidine dose intensity during chemotherapy was 50%. No grade ≥3 toxicities were observed. DPYD*2A test results were available in an average of 6 days, causing no significant delays in treatment initiation.

CONCLUSION

Upfront genotyping before fluoropyrimidine-based treatment is feasible in clinical practice and can prevent severe toxicities and hospitalizations without delaying treatment initiation. The administration of chemotherapy at reduced doses appears to be safe in patients heterozygous for DPYD*2A.

IMPLICATIONS FOR PRACTICE

Fluoropyrimidines are part of chemotherapy combinations for multiple cancers. Deficient dihydropyrimidine dehydrogenase activity can lead to severe life-threatening toxicities. This retrospective analysis demonstrates that upfront genotyping of DPYD before fluoropyrimidine-based treatment is feasible in clinical practice and can prevent severe toxicities and hospitalizations without delaying treatment initiation. This approach was reported previously, but insufficient data concerning its application in real practice are available. This is likely the first reported experience of systematic DPYD genotyping all over Canada and North America as well.

Interleukin-1 receptor antagonist enhances chemosensitivity to fluorouracil in treatment of Kras mutant colon cancer

BACKGROUND

Kras mutant colon cancer shows abnormal activation of the nuclear factor kappa-B (NF-κB) pathway, resulting in the proliferation of tumor cells. Treatment with fluorouracil (5-FU) might not achieve the expected inhibition of proliferation of malignant cells based on the fluorouracil-induced activation of the NF-κB pathway.

AIM

To detect whether interleukin (IL)-1 receptor antagonist (IL-1RA) could increase the chemosensitivity to 5-FU by decreasing the activation of the NF-κB pathway and reducing the proliferation of colon cancer cells.

METHODS

Western blot analysis was performed to detect the persistent activation of the NF-κB pathway in colon cancer cell lines. Reverse transcription-polymerase chain reaction was used to detect the IL-1RA-reduced expression levels of IL-6, IL-8, IL-17, IL-21 and TLR4 in colon cancer cell lines. We used a xenograft nude mouse model to demonstrate the downregulation of the NF-κB pathway by blocking the NF-κB-regulated IL-1α feedforward loop, which could increase the efficacy of chemotherapeutic agents in inhibiting tumor cell growth.

RESULTS

IL-1 receptor antagonist could decrease the expression of IL-1α and IL-1β and downregulate the activity of the NF-κB pathway in Kras mutant colon cancer cells. Treatment with 5-FU combined with IL-1RA could increase the chemosensitivity of the SW620 cell line, and decreased expression of the TAK1/NF-κB and MEK pathways resulted in limited proliferation in the SW620 cell line.

CONCLUSION

Adjuvant chemotherapy with IL-1RA and 5-FU has a stronger effect than single chemotherapeutic drugs. IL-1RA combined with fluorouracil could be a potential neoadjuvant chemotherapy in the clinic.

Discoid Lupus Erythematosus Lesions Associated with Systemic Fluorouracil Agents: A Case Report and Review

Systemic fluorouracil agents include not only 5-fluorouracil (5FU), but also capecitabine, tegafur, and uracil/tegafur (UFT). Systemic lupus erythematosus (SLE), subacute cutaneous lupus erythematosus (SCLE), and discoid lupus erythematosus (DLE) are subtypes of lupus erythematosus; drug-induced lupus erythematosus can also present in each of these subtypes. This report describes the case of a 65-year-old woman with systemic 5FU-induced DLE. Fluorouracil agent-induced DLE lesions occurring after initiating treatment with either systemic 5FU or its prodrugs have been described in 19 individuals (Including the woman in this report) in the literature: tegafur (10 patients), UFT (six patients), systemic 5FU (two patients), and capecitabine (one patient). The mean duration before the appearance of the DLE lesions on sun-exposed areas was 232 days after beginning the fluorouracil agent; however, the much earlier (three weeks) appearance of the DLE lesions after starting systemic 5FU in the women described in this report may have occurred since there was no delay associated with the conversion of a precursor drug to 5FU. Within two months (mean: 36 days) after stopping the fluorouracil agent, the DLE lesions resolved in 95% of the patients. Laboratory studies were only performed on some of the patients. None of the patients tested had antibodies to Ro/Sjogren’s syndrome A (Ro/SSA) and La/Sjogren’s syndrome B (La/SSB). The antinuclear antibody (ANA) titer was elevated in 71% of the tested individuals and decreased in all of the patients who were evaluated after the causative drug was discontinued. The pathogenesis for fluorouracil agent drug-induced DLE remains to be definitively established.

Synthesis of novel 6-substituted amino-9-(β-d-ribofuranosyl)purine analogs and their bioactivities on human epithelial cancer cells

New nucleoside derivatives with nitrogen substitution at the C-6 position were prepared and screened initially for their in vitro anticancer bioactivity against human epithelial cancer cells (liver Huh7, colon HCT116, breast MCF7) by the NCI-sulforhodamine B assay. N⁶-(4-trifluoromethylphenyl)piperazine analog (27) exhibited promising cytotoxic activity. The compound 27 was more cytotoxic (IC₅₀ = 1-4 μM) than 5-FU, fludarabine on Huh7, HCT116 and MCF7 cell lines. The most potent nucleosides (11, 13, 16, 18, 19, 21, 27, 28) were further screened for their cytotoxicity in hepatocellular cancer cell lines. The compound 27 demonstrated the highest cytotoxic activity against Huh7, Mahlavu and FOCUS cells (IC₅₀ = 1, 3 and 1 μM respectively). Physicochemical properties, drug-likeness, and drug score profiles of the molecules showed that they are estimated to be orally bioavailable. The results pointed that the novel derivatives would be potential drug candidates.

The effects of genomic polymorphisms in one-carbon metabolism pathways on survival of gastric cancer patients received fluorouracil-based adjuvant therapy

5-fluorouracil (5-FU) is widely used to treat patients with gastric cancer (GC). However, the response rate is quite heterogeneous. The single nucleotide polymorphisms (SNPs) and their interactions of genes in the one-carbon metabolism (OCM) pathway, including Methylenetetrahydrofolate reductase (MTHFR), Methionine synthase reductase (MTRR), Methionine synthase (MTR), and Thymidylate synthase (TS), significantly affect 5-FU metabolism. In this study, 650 stage II-III patients were recruited from 1998 to 2006. Among them, 251 received 5-FU treatment and other 399 patients were untreated. The Cox regression analysis, log-rank tests and Kaplan-Meier plots were adopted. In the chemotherapy cohort, MTRR 66 GA + GG genotypes decreased death risk, however, the protect effect of MTRR 66 GA + GG disappeared when GC patients simultaneously had MTHFR 677TT + TC or MTR 2756GG + GA genotypes. TS 5'-UTR 2R3R + 3R3R genotypes also prolonged overall survival of patients treated with 5-FU. And this favorable prognosis obviously enhanced when GC patients simultaneously had TS 3'-UTR DD + DI and TS 5'-UTR 2R3R + 3R3R genotypes. Our findings showed that the polymorphisms of MTRR 66 A > G and TS 5'-UTR 3R > 2R may be potential prognostic factors for GC patients receiving 5-FU.

Icariin-mediated inhibition of NF-κB activity enhances the in vitro and in vivo antitumour effect of 5-fluorouracil in colorectal cancer

Colorectal cancer (CRC) is an aggressive malignancy that has a poor prognosis. 5-Fluorouracil (5-FU) is a first line chemotherapeutic medication used in the treatment of gallbladder cancer; however, the efficacy is below satisfactory. Icariin is a natural compound that is conventionally reported to have activity against a variety of cancers. This study was carried out to investigate the anti-cancer effect of icariin in CRC cells and to determine whether the compound can enhance the antitumour activity of 5-FU. Cell proliferation and apoptosis were measured using an MTT assay and flow cytometry, respectively. The activity of transcription factor NF-κB was determined by EMSA method. The expression of apoptosis- and proliferation-related proteins was determined by western blotting. The in vivo antitumour effect of combination treatment with icariin and 5-FU on CRC was also assessed using a murine model of CRC. Icariin sensitized the CRC cells to 5-FU both in vitro and in vivo. The antitumour activity of icariin and its potentiating effect on the antitumour activity of 5-FU implicated the suppression of NF-κB activity and consequent down-regulation of the gene products regulated by NF-κB. Our results showed that icariin, suppressed tumour growth and enhanced the antitumour activity of 5-FU in CRC by inhibiting NF-κB activity. Therefore, we suggest that combination of icariin with 5-FU might offer a therapeutic benefit to the patients with CRC; however, further studies are required to ascertain this proposition.

Relationship of MTHFR and NQO1 Pharmacogenetics and Chemotherapy Clinical Outcomes in Breast Cancer Patients

The study aimed at evaluating the influence of MTHFR 677C>T and NQO1 609C>T polymorphisms in toxicity and response to chemotherapy in breast cancer patients. These two genes are involved in the folate homeostasis and bioactivation of chemotherapeutic drugs, respectively. In this study, 243 patients treated with FEC/FAC/methotrexate chemotherapy regimen were recruited and followed up for toxicity (NCI-CTCAE ver. 3). While out of 243 patients, 115 patients who received neo-adjuvant chemotherapy (NACT) were followed for treatment response. Genetic analysis of MTHFR 677C>T and NQO1 609C>T was done by PCR-restriction fragment length polymorphism. We found significant association of variant genotype (TT) of NQO1 609C>T with grade 2-4 toxicity [OR 0.33 (0.13-0.88), P = 0.027] and with grade 2-4 anemia [OR 0.34 (0.12-0.95), P = 0.041]. However, no association of MTHFR 677C>T was seen with either response to NACT or drug-induced toxicity. The study provides useful information for prediction of clinical outcomes in breast cancer patients in terms of NQO1 609C>T by evaluating its association with chemotherapy-induced toxicity.

Synthesis of novel substituted purine derivatives and identification of the cell death mechanism

Novel 9-(substituted amino/piperazinoethyl)adenines (4-12), 6-(substituted piperazino/amino)purines (15-27), 9-(p-toluenesulfonyl/cyclopentyl/ethoxycarbonylmethyl)-6-(substituted amino/piperazino)purines (28-34, 36, 37, 38-41) were synthesized and evaluated initially for their cytotoxic activities on liver Huh7, breast T47D and colon HCT116 carcinoma cells. N(6)-(4-Trifluoromethylphenyl)piperazine derivative (17) and its 9-(p-toluene-sulfonyl)/9-cyclopentyl analogues (28, 36) had promising cytotoxic activities. Compounds 17, 28 and 36 were further analysed for their cytotoxicity in a panel of a liver cancer cell lines. The compound 36 had better cytotoxic activities (IC50 ≤ 1 μM) than the nucleobase 5-FU and nucleosides fludarabine, cladribine, and pentostatine on Huh7 cells. Cytotoxicity induced by 36 was later identified as senescence associated cell death by SA-β-Gal assay.

Evolving approaches to metastatic breast cancer patients pre-treated with anthracycline and taxane

Metastatic breast cancer is currently incurable and the goals of therapy focus on prolonging survival and maintaining quality of life by controlling symptoms and minimizing toxicity. Treatments for metastatic breast cancer include chemotherapeutic agents from various classes, such as taxanes, vinca alkaloids, anthracyclines and antimetabolites. This review provides an overview of chemotherapeutic agents for the treatment of metastatic breast cancer patients previously treated with anthracyclines and taxanes, focusing on a clinical evaluation of eribulin, the most recently approved agent for the treatment of metastatic breast cancer. Eribulin is a synthetic derivative of halichondrin B, a tumour growth inhibitor found in marine sponges, which prevents microtubule growth and sequesters the tubulin molecules into unusual aggregates, initiating apoptosis. Studies of eribulin have shown that the drug is effective in the treatment of previously treated metastatic breast cancer, and has an acceptable toxicity profile. Importantly, in the phase III EMBRACE study, eribulin treatment resulted in a survival advantage, a difficult endpoint to achieve with a single chemotherapeutic agent. An additional phase III study showed that eribulin has similar efficacy to capecitabine in women treated with no more than three prior therapies. Furthermore, pre-specified exploratory analyses suggest that particular patient subgroups may have greater therapeutic benefit with eribulin and may warrant further study to explore the potential mechanisms.

Impact of the MTHFR C677T polymorphism on colorectal cancer in a population with low genetic variability

PURPOSES

Methylenetetrahydrofolate reductase (MTHFR) plays a key role in folate metabolism, and folate is implicated in carcinogenesis by its role in DNA methylation, repair, and synthesis. We analyzed the impact of MTHFR C677T polymorphism in colorectal cancer in a region of the Tenerife Island whose population has a history of genetic isolation and a low genetic variability. This allows analyzing the effects of the polymorphism that are not due to interactions with different genetic variants.

METHODS

Genomic DNA of 50 Spanish sporadic colorectal cancer (CRC) patients and 103 controls was analyzed by PCR/RFLP and sequencing.

RESULTS

The T allele is more frequent in controls than in patients (P < 0.01). The variant (T) carriers displayed significant odds ratio values for the CT heterozygotes (P = 0.026) and even when grouping heterozygote (CT) and homozygotes (TT) (P = 0.015). Patients carriers of the variant T (CT y TT) show a higher survival rate after chemotherapy than the CC homozygotes (log rank; P = 0.001).

CONCLUSIONS

The MTHRF C677T variant has a protective effect on CRC development in a population with low allelic variability and an optimal intake of folic acid. Moreover, patients carrying the variant (T) show a better prognosis after 5-fluorouracil/folinic acid-based chemotherapy.

Synergistic antitumor effect of 5-fluorouracil in combination with parthenolide in human colorectal cancer

Parthenolide (PT), a NF-κB inhibitor, has recently been demonstrated as a promising anticancer agent that promotes apoptosis of cancer cells. 5-fluorouracil (5-FU) has been a drug of choice for treatment of colorectal cancer (CRC). Unfortunately, many of the therapies that use 5-FU alone or in combination with other agents are likely to become ineffective due to drug resistance. In the present study, we investigated the antitumor effect of PT combined with 5-FU on a human CRC cell line, SW620. The results demonstrated that combination of PT and 5-FU induced apoptosis which was determined using MTT, cell cycle analysis, annexin-V assay, and Hoechst 33258 staining. Apoptosis through the mitochondrial pathway was confirmed by detecting regulation of Bcl-2 family members, cytochrome C release, and activation of caspase 3 and 9. Moreover, intra-peritoneal injection of PT and 5-FU showed significant inhibition of tumor growth in the xenograft model. These results demonstrate that PT exhibits anticancer activity in human colorectal cancer in vitro and in vivo. These findings provide an efficacious strategy to overcome 5-FU resistance in certain CRC.

DTNQ-Pro, a Mimetic Dipeptide, Sensitizes Human Colon Cancer Cells to 5-Fluorouracil Treatment

The resistance of growing human colon cancer cells to chemotherapy agents has been correlated to endogenous overexpression of stress proteins including the family of heat shock proteins (HSPs). Previously, we have demonstrated that a quinone-based mimetic dipeptide, named DTNQ-Pro, induced differentiation of growing Caco-2 cells through inhibition of HSP70 and HSP90. In addition, our product induced a HSP27 and vimentin intracellular redistribution. In the present study, we have evaluated whether a decrease of stress proteins induced by DTNQ-Pro in Caco-2 cells could sensitize these cells to treatment with 5-fluorouracil (5-FU) cytotoxicity. The pretreatment of Caco-2 with 500 nM of DTNQ-Pro increases lipid peroxidation and decreases expression of p38 mitogen-activated protein kinase (MAPK) and FOXO3a. At the same experimental conditions, an increase of the 5-FU-induced growth inhibition of Caco-2 cells was recorded. These effects could be due to enhanced DTNQ-Pro-induced membrane lipid peroxidation that, in turn, causes the sensitization of cancer cells to the cytotoxicity mediated by 5-FU.

Oral uracil-tegafur plus leucovorin vs fluorouracil bolus plus leucovorin for advanced colorectal cancer: a meta-analysis of five randomized controlled trials

AIM

The aim of this study was to evaluate systematically the efficacy and safety of oral uracil-tegafur (UFT) plus leucovorin (LV) compared with infusional fluorouracil (5-FU) plus LV for advanced colorectal cancer.

METHOD

Eligible studies were identified from Medline, Embase and the Cochrane Library. The end-points included overall survival and overall tumour response rate, and toxicity including leucopenia, febrile neutropenia, stomatitis/mucositis and diarrhoea.

RESULTS

Five randomized controlled trials were identified. Pooled data demonstrated no difference in overall survival between the oral UFT plus LV regimen and the 5-FU bolus plus LV regimen [hazard ratio 1.013; 95% confidence interval (CI) 0.911-1.127].The fixed-effect pooled estimate for overall tumour response rate showed no significant difference between the two regimens (relative risk 0.893; 0.672-1.187). Grade 3-4 leucopenia [odds ratio (OR) 0.126; 955 CI 0.048-0.326], grade 1-4 leucopenia (OR 0.089; 95% CI 0.067-0.119) and grade1-4 febrile neutropenia (OR 0.020; 95% CI 0.004-0.102) were significantly less prominent in the oral UFT regimens. For nonhaematological toxicities, grade 3-4 stomatitis/mucositis (OR 0.075; 95% CI 0.039-0.146), grade 3-4 infection (OR 0.484; 95% CI 0.310-0.758), grade 1-4 infection (OR 0.672; 95% CI 0.547-0.826, P < 0.001), grade 1-4 diarrhoea (OR 0.743; 95% CI 0.626-0.881) were also less likely to happen in patients in the oral UFT plus LV regimen, while there was no significant difference between the two treatment regimens with respect to grade 1-4 stomatitis/mucositis (OR 0.278; 95% CI 0.053-1.456) and grade 3-4 (OR 1.174; 95% CI 0.983-1.403) diarrhoea.

CONCLUSION

Oral UFT or 5-FU bolus combined with LV results in similar overall survival and tumour response rates for advanced colorectal cancer. The former treatment regimen is greatly superior in terms of toxicity, especially haematological toxicity.

Higher expression of deoxyuridine triphosphatase (dUTPase) may predict the metastasis potential of colorectal cancer

Aims:

5-Fluorouracil (5-FU) is one of the most widely used anticancer drugs; however, the activity of 5-FU is determined by the presence of several enzymes that limit its activation or degradation, and these include dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), thymidine kinase (TK), thymidine phosphorylase (TP) and deoxyuridine triphosphatase (dUTPase). The aim of this study was to compare the expression levels of these enzymes between the primary colorectal cancer of patients with and without distant metastases. Furthermore, there was a comparison of these expression levels between the primary tumour and the corresponding metastasis.

Methods:

Of 55 patients with colorectal cancer, 20 had no metastasis and the other 35 had distant metastasis. A strong expression was classified as positive, while weak to moderate or no expression was negative by immunohistochemistry.

Results:

Of the six 5-FU-related enzymes, the numbers of patients with expression of dUTPase (54% versus 15%; p = 0.005), TK (26% versus 0%; p = 0.019) and DPD (17% versus 45%; p = 0.033) were significantly different in those with primary tumours with metastasis compared with those with non-metastasis, respectively. The altered expression of OPRT (34.3%), TS (40.0%) and dUTPase (42.9%) was significantly greater from primary to metastasis among the 35 patients with metastasis. By contrast, the expression of OPRT, TS and dUTPase was decreased in 6, 5 and 7 patients, respectively, in metastatic sites.

Conclusions:

From this comparative study of the six 5-FU-related enzymes in colorectal cancer, the expression of dUTPase was most significantly different between primary tumours and their corresponding metastatic tumour. It is suggested that dUTPase may be a predictive biomarker for the metastatic potential of colorectal cancer.

Effect of cystathionine beta-synthase variant 844ins68bp and methylenetetrahydrofolate reductase A1298C polymorphisms in xenografts on 5-FU efficacy and doubling time

The association of MTHFR and CBS variants with the doubling time and responsiveness to several chemodrugs was analyzed in 26 human cancer xenografts. The tumors homozygous for the absence of insertion (NN) for the CBS 844ins68bp were more chemosensitive than those with insertion (NI) to TS-1 (P=0.0048), suggesting a potential effect of this variant on fluoropyrimidine efficacy. Furthermore, the doubling time of tumors with a variant C allele (AC or CC) in MTHFR-A1298C was significantly longer than that of tumors with a normal allele (AA) (P=0.0008). Twenty-nine cellular proliferation-related genes were associated with MTHFR-A1298C genotyping and with the doubling time.

Methylenetetrahydrofolate reductase C677T is not associated with expression of pyrimidine metabolic enzyme genes in colorectal cancer

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may influence the chemosensitivity of colorectal cancers to fluorouracil (5-FU) by increasing intracellular 5,10-methylenetetrahydrofolate. The effect of this polymorphism on the expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) and thymidine phosphorylase (TP) in colorectal cancer was investigated. The MTHFR C677T polymorphism was analysed and TS, DPD, OPRT and TP mRNA expression was measured in tumour and adjacent normal mucosal tissue. In all patients, the genotypes of the tumour and normal tissues were identical. No differences were found in the expression of TS, DPD or TP mRNA by genotype in either tumour or normal tissue. Although the OPRT mRNA level in tumour tissue was not associated with the genotype, normal mucosa with the TT genotype showed a significantly higher OPRT mRNA level than mucosa with other genotypes. The MTHFR C667T polymorphism is not associated with intratumoural expression of TS, DPD, OPRT or TP.

Multidisciplinary Therapy of Locally Far‐Advanced or Inflammatory Breast Cancer with Fixed Perioperative Sequence of Epirubicin, Vinorelbine, and Fluorouracil Chemotherapy, Surgery, and Radiotherapy: Long‐Term Results

BACKGROUND

Based on phase II data in advanced breast cancer (BC), the fluorouracil, epirubicin, and vinorelbine (FEN) combination was assessed as perioperative chemotherapy, integrated in a multidisciplinary treatment for locally advanced BC.

PATIENTS AND METHODS

Patients with newly diagnosed inoperable (stage IIIB or inflammatory) BC. Multimodality treatment protocol consisted of four preoperative courses of fluorouracil (600 mg/m(2) day 1), epirubicin (75 mg/m(2) day 1), and vinorelbine (25 mg/m(2) day1 and day 8), all i.v. every 21 days, followed by radical or conservative surgery according to clinical response and four postoperative identical chemotherapy courses aimed to eradicate micrometastatic disease. Locoregional radiotherapy was offered to all patients after the completion of chemotherapy followed by hormonotherapy according to hormone receptor status. The primary end points of the study were: (a) clinical and pathological response, (b) downstaging and conversion to operable disease, and (c) recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Forty-eight women, one stage IIIA, 27 (56.2%) stage IIIB, two stage IIIC (4.1%), and 12 (25%) with inflammatory BC, aged 34-75 years (median, 52), were accrued. Thirty-eight and 34 patients completed the planned pre- and postoperative chemotherapy, respectively. Totals of 175 and 135 cycles were administered pre- and postoperatively, respectively. Toxicity of both phases, mainly hematologic, was in general acceptable without treatment-related death. Venous reactions were a frequent problem. All but three tumors were converted to operable, 31.3% with breast conservation. The clinical response rate (RR) was 77.7% (22.2% complete) and pathological RR was 73.3% (complete, 20% in both primary and axilla). After a median follow-up of 72 months, 62.5% and 16.7% of patients remain relapse free at 3 and 5 years, respectively, while 83% and 58.3% were alive 3 and 5 years, respectively, after the start of chemotherapy. Median RFS and OS have not yet been reached, and are currently 37+ and 62+ months, respectively.

CONCLUSION

This fixed number of FEN perioperative courses schedule followed by radiotherapy is safe and highly active in inducing both local and distant control of locally far-advanced BC. This strategy is at least not inferior to other established regimens or strategies for locally far-advanced BC, while the integration of taxanes or new targeted agents may help show its true value for this challenging clinical entity.

Genetic factors influencing pyrimidine-antagonist chemotherapy

Pyrimidine antagonists, for example, 5-fluorouracil (5-FU), cytarabine (ara-C) and gemcitabine (dFdC), are widely used in chemotherapy regimes for colorectal, breast, head and neck, non-small-cell lung cancer, pancreatic cancer and leukaemias. Extensive metabolism is a prerequisite for conversion of these pyrimidine prodrugs into active compounds. Interindividual variation in the activity of metabolising enzymes can affect the extent of prodrug activation and, as a result, act on the efficacy of chemotherapy treatment. Genetic factors at least partly explain interindividual variation in antitumour efficacy and toxicity of pyrimidine antagonists. In this review, proteins relevant for the efficacy and toxicity of pyrimidine antagonists will be summarised. In addition, the role of germline polymorphisms, tumour-specific somatic mutations and protein expression levels in the metabolic pathways and clinical pharmacology of these drugs are described. Germline polymorphisms of uridine monophosphate kinase (UMPK), orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and methylene tetrahydrofolate reductase (MTHFR) and gene expression levels of OPRT, UMPK, TS, DPD, uridine phosphorylase, uridine kinase, thymidine phosphorylase, thymidine kinase, deoxyuridine triphosphate nucleotide hydrolase are discussed in relation to 5-FU efficacy. Cytidine deaminase (CDD) and 5'-nucleotidase (5NT) gene polymorphisms and CDD, 5NT, deoxycytidine kinase and MRP5 gene expression levels and their potential relation to dFdC and ara-C cytotoxicity are reviewed.

Antitumor activity of novel N-sulfonylpyrimidine derivatives on the growth of anaplastic mammary carcinoma in vivo

PURPOSE

The purpose of this study was to investigate in vivo antitumor activity of newly synthesized N-sulfonylpyrimidine derivatives 1-(p-toluenesulfonyl)cytosine (4H), 1-(p-toluenesulfonyl)cytosine hydrochloride (4HxHCl) and zinc(II) complex of 1-(p-toluenesulfonyl)cytosine (4K).

MATERIALS AND METHODS

In order to do that we have used mouse anaplastic mammary carcinoma (AMCa). Tumor cells (10(6)) in a volume of 0.02 ml were transplanted into the thigh of the right hind leg of CBA mice. All compounds were dissolved in distilled water immediately before injecting to animals.

RESULTS

Antitumor effect of these compounds depends on drug doses and time interval between tumor transplantation and drug application. Further the efficacy of these compounds depends on number of drug injections, i. e. whether drug was given in single or in multiple doses. Multiple doses of 400 mg/kg of 1-(p-toluenesulfonyl)cytosine (4H) showed good antitumor effect when applied on day 1, 3, 5, 7 and 9 after tumor transplantation. Still good but slightly lower antitumor effect was also achieved when that compound was given in a single dose (1,200 mg/kg) on day 1 after tumor transplantation. The longest period of tumor growth time was obtained after application of 1-(p-toluenesulfonyl)cytosine hydrochloride (4HxHCl) given as a single dose (300 mg/kg) on day 1 or on day 6 after tumor implantation. However, antitumor effect of zinc(II) complex of 1-(p-toluenesulfonyl)cytosine (4K) was very strong when 300 mg/kg was given on day 1 or day 6, while this effect was slightly lower when drug (200 mg/kg/inj) was given on day 1, 3, 5, 7 and 9 or on day 6, 8, 10, 12 and 14.

CONCLUSION

In this work it has been found that N-1-sulfonylcytosine derivatives have strong antitumor activity against mouse mammary carcinoma which is a good reason for further research of these compounds both in experimental and preclinical studies.

Olfactory epithelial lesions induced by various cancer chemotherapeutic agents in mice

In order to examine and compare the potential toxicity in the olfactory epithelium, the antitumor drug vincristine sulfate (VCR), vinblastine sulfate(VBL), vindesine sulfate (VDS), paclitaxel (PTX), mitomycin C (MMC), 5-fluorouracil, (5-FU) or cisplatin (CDDP) was intravenously injected once(designated as day 1) at an estimated 10% lethal dose (LD(10)) to male BALB/c mice. The animals were necropsied on days 2, 5 and 15, and nasal tissues were examined by light-microscopy, counting of epithelial cells positive for terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL), immunohistochemical staining with keratin antibody, and electron microscopy. Further, to delineate the drug disposition in the target organ, whole-body radioluminography was performed 1 hour and 24 hours after treatment with the LD(10) of PTX or 5-FU. Of the antitumor drugs employed, only the antimicrotubule agents, VCR, VBL, VDS, and PTX, induced single cell death in the olfactory epithelium, especially sensory cells on day 2, atrophy of the olfactory epithelium on day 5, and myelin fragmentation in the trigeminal nerve on day 15. PTX induced the strongest changes among the 4 antimicrotubule agents. The cell death was confirmed to be apoptosis by TUNEL assay and electron microscopy, whereas the change in horizontal basal cells of the olfactory epithelium was shown not to be apoptosis by keratin staining. In quantitative radioluminography,radioactivity of PTX in the nasal tissues both 1 hour and 24 hours after administration was about 4- or 5-fold higher than those of 5-FU. These results suggest that tubulin-targeting antitumour drugs could induce apoptosis in the olfactory epithelial cells of mice and that high drug distribution may effect the onset of the olfactory lesions.

Synthesis of [18F]Xeloda as a novel potential PET radiotracer for imaging enzymes in cancers

Xeloda (Capecitabine), a prodrug of antitumor agent 5-fluorouracil, is the first and only oral fluoropyrimidine to be approved for use as second-line therapy in metastatic breast cancer, colorectal cancer, and other solid malignancies. Fluorine-18 labeled Xeloda may serve as a novel radiotracer for positron emission tomography (PET) to image enzymes such as thymidine phosphorylase and uridine phosphorylase in cancers. The precursor 2',3'-di-O-acetyl-5'-deoxy-5-nitro-N(4)-(pentyloxycarbonyl)cytidine (11) was synthesized from D-ribose and cytosine in 8 steps with approximately 18% overall chemical yield. The reference standard 5'-deoxy-5-fluoro-N(4)-(pentyloxycarbonyl)cytidine (Xeloda; 1) was synthesized from D-ribose and 5-fluorocytosine in eight steps with approximately 28% overall chemical yield. The target radiotracer 5'-deoxy-5-[(18)F]fluoro-N(4)-(pentyloxycarbonyl)cytidine ([(18)F]Xeloda; [(18)F]1) was prepared by nucleophilic substitution of the nitro-precursor with K(18)F/Kryptofix 2.2.2 followed by a quick deprotection reaction and purification with the HPLC method in 20-30% radiochemical yields.

Weekly high-dose 5-fluorouracil and folinic acid in metastatic pancreatic carcinoma: a phase II study of the EORTC GastroIntestinal Tract Cancer Cooperative Group

The aim of the study was to assess the response rate and toxicity of high-dose 24 h infusion of 5-fluorouracil (5FU) in metastatic adenocarcinoma of the pancreas. Patients with measurable disease, performance status 0-2, and no prior chemotherapy were registered to receive cycles of leucovorin (LV) 500 mg/m2 (or l-LV 250 mg/m2 over 1 h followed by 5FU 2.6 g/m2 over 24 h, weekly for 6 weeks, followed by a 2-week rest. The main endpoints were the response rate and toxicity. From 37 patients, 36 were the analysed for toxicity, and 33 were eligible and analysed for response. The median age was 59 years (range 28-74 years), and the median performance status was 1. Partial response was observed in three patients (9%) (95% Confidential Interval (CI): [2-24]%). Main grade 3/4 National Cancer Institute (NCI) common toxicity criteria toxicities (patients) were diarrhoea (n = 3), vomiting (n = 2) and hand-foot syndrome (n = 5). Median time to progression was 7 weeks (95% CI: [6.4-11.7] weeks) and median survival 19 weeks (95% CI: [12-35] weeks). In conclusion, high-dose 5FU and folinic acid is well tolerated, but has only modest activity in pancreatic cancer.

Effect of the methylenetetrahydrofolate reductase C677T polymorphism on chemosensitivity of colon and breast cancer cells to 5-fluorouracil and methotrexate

BACKGROUND

Although single nucleotide polymorphisms may be potentially important pharmacogenetic determinants of cancer therapy, functional evidence regarding their relevance is currently lacking. The C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with changes in cellular composition of folates. We hypothesized that this polymorphism may modulate the cytotoxic effect of 5-fluorouracil (5FU) and methotrexate (MTX), two commonly used chemotherapeutic agents for colon and breast cancers, because the modes of action of 5FU and MTX are critically dependent on cellular composition of folates.

METHODS

Human HCT116 colon and MDA-MB-435 breast cancer cells were stably transfected with wild-type or mutant 677T human MTHFR cDNA. MTHFR enzyme activity and thermolability, intracellular folate composition, growth rate, and catalytic thymidylate synthase activity were determined. In vitro chemosensitivity to 5FU and MTX was determined using the sulforhodamine B assay. In vivo chemosensitivity of HCT116 cells to 5FU was determined in nude mice.

RESULTS

Compared with cells expressing the wild-type MTHFR, HCT116 and MDA-MB-435 cells expressing the mutant 677T MTHFR had decreased MTHFR activity, MTHFR thermolability, changed intracellular folate distribution, accelerated cellular growth rate, and increased thymidylate synthase activity. The MTHFR 677T mutation increased chemosensitivity of colon and breast cancers to 5FU, but decreased chemosensitivity of breast cancer cells to MTX. In nude mice, xenografts expressing the mutant 677T MTHFR grew faster, but were more sensitive to 5FU, than xenografts expressing the wild-type protein.

CONCLUSIONS

Our data provide evidence that the MTHFR C677T polymorphism affects the concentration and intracellular distribution of folates and changes the growth and chemosensitivity of colon and breast cancer cells. The MTHFR C677T polymorphism may be a useful pharmacogenetic determinant for providing rational and effective tailored chemotherapy.

Current Canadian experience with capecitabine: partnering with patients to optimize therapy

Capecitabine (Xeloda) is the first oral chemotherapeutic agent to be used in Canada for the treatment of metastatic breast cancer and metastatic colorectal cancer. The home-based administration of this drug, coupled with the importance of prompt side-effect management, presents unique challenges to oncology nurses and gives them an expanded role in optimizing therapeutic outcomes. Fulfillment of this role involves partnering with patients to help them become educated active participants in their own treatment, and to ensure that side effects are prevented, recognized, and managed adeptly. Although well tolerated, capecitabine, as with all chemotherapy, can require interventions and dose modification. Hand-foot syndrome, the most common dose-limiting toxicity, requires particular attention. Drawing from published articles and interviews with Canadian oncology care providers, this article reviews the development and safety profile of capecitabine. Best practices in side-effect management are discussed, with a particular focus on managing hand-foot syndrome and building patient partnerships.

Strategies for improving quality of life in older patients with metastatic breast cancer

Given both the increase in the mean age of the population of Western countries and the high incidence of breast cancer beyond the age of 65 years, it is evident that breast cancer in older women will be a very common problem for the medical oncologist. Metastatic breast cancer is still not amenable to a cure; therefore quality of life during therapy is an important issue, which until recently has been poorly investigated. Similarly, despite recent advances in breast cancer therapy, physicians have been reluctant to enrol older patients in clinical trials, and there is a lack of data regarding this population. This review focuses on quality-of-life issues during metastatic breast cancer treatment in geriatric patients, comparing the standard therapeutic options and newer approaches. Although first-line endocrine therapy with tamoxifen remains a standard treatment, the newer third-generation aromatase inhibitors provide similar or better efficacy with fewer adverse effects and a better quality of life. It has been a common belief that chemotherapy impairs quality of life, but recent studies in advanced breast cancer have shown that this therapy has a positive effect on quality of life, at least in responders. Consequently, chemotherapy should not be denied to elderly patients with metastatic breast cancer, provided a prior geriatric assessment is performed to evaluate the risk-benefit ratio. New chemotherapy strategies, such as the taxanes and orally administered chemotherapy, represent a very attractive alternative for a better quality of life in elderly patients with metastatic breast cancer.

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

Although 5-fluorouracil (5-FU) was first introduced in 1957, it remains an essential part of the treatment of a wide range of solid tumors. 5-FU has antitumor activity against epithelial malignancies arising in the gastrointestinal tract and breast as well as the head and neck, with single-agent response rates of only 10%-30%. Although 5-FU is still the most widely prescribed agent for the treatment of colorectal cancer, less than one-third of patients achieve objective responses. Recent research has focused on the biomodulation of 5-FU to improve the cytotoxicity and therapeutic effectiveness of this drug in the treatment of advanced disease. As all the anticancer agents, 5-FU leads to several toxicities. The toxicity profile of 5-FU is schedule dependent. Myelotoxicity is the major toxic effect in patients receiving bolus doses. Hand-foot syndrome (palmar-plantar erythrodysesthesia), stomatitis, and neuro- and cardiotoxicities are associated with continuous infusions. Other adverse effects associated with both bolus-dose and continuous-infusion regimens include nausea and vomiting, diarrhea, alopecia, and dermatitis. All these reasons explain the need for more effective and less toxic fluoropyrimidines. In the first part of this review, we briefly present the metabolic pathways of 5-FU responsible for the efficacy and toxicity of this drug. This knowledge is also necessary to understand the target(s) of biomodulation. The second part is devoted to a review of the literature on three recent prodrugs of 5-FU, i.e., capecitabine, UFT (ftorafur [FTO] plus uracil), and S-1 (FTO plus 5-chloro-2,4-dihydroxypyridine plus potassium oxonate). The pharmacological principles that have influenced the development of these new drugs and our current knowledge of the clinical pharmacology of these new agents, focusing on antitumor activity and toxicity, are presented. The literature was analyzed until March 2002. This review is intended to be as exhaustive as possible since it was conceived as a work tool for readers wanting to go further.