A phase I open-label, dose-escalation study of NUC-3373, a targeted thymidylate synthase inhibitor, in patients with advanced cancer (NuTide:301).

PURPOSE: 5-fluorouracil (5-FU) is inefficiently converted to the active anti-cancer metabolite, fluorodeoxyuridine-monophosphate (FUDR-MP), is associated with dose-limiting toxicities and challenging administration schedules. NUC-3373 is a phosphoramidate nucleotide analog of fluorodeoxyuridine (FUDR) designed to overcome these limitations and replace fluoropyrimidines such as 5-FU. PATIENTS AND METHODS: NUC-3373 was administered as monotherapy to patients with advanced solid tumors refractory to standard therapy via intravenous infusion either on Days 1, 8, 15 and 22 (Part 1) or on Days 1 and 15 (Part 2) of 28-day cycles until disease progression or unacceptable toxicity. Primary objectives were maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) and schedule of NUC-3373. Secondary objectives included pharmacokinetics (PK), and anti-tumor activity. RESULTS: Fifty-nine patients received weekly NUC-3373 in 9 cohorts in Part 1 (n = 43) and 3 alternate-weekly dosing cohorts in Part 2 (n = 16). They had received a median of 3 prior lines of treatment (range: 0-11) and 74% were exposed to prior fluoropyrimidines. Four experienced dose-limiting toxicities: two Grade (G) 3 transaminitis; one G2 headache; and one G3 transient hypotension. Commonest treatment-related G3 adverse event of raised transaminases occurred in < 10% of patients. NUC-3373 showed a favorable PK profile, with dose-proportionality and a prolonged half-life compared to 5-FU. A best overall response of stable disease was observed, with prolonged progression-free survival. CONCLUSION: NUC-3373 was well-tolerated in a heavily pre-treated solid tumor patient population, including those who had relapsed on prior 5-FU. The MTD and RP2D was defined as 2500 mg/m2 NUC-3373 weekly. NUC-3373 is currently in combination treatment studies. TRIAL REGISTRATION: Clinicaltrials.gov registry number NCT02723240. Trial registered on 8th December 2015. https://clinicaltrials.gov/study/NCT02723240 .

Case-Based Clinical Guidance on Dosing and Management of the Hepatic Artery Infusion Chemotherapy Pump.

Hepatic artery infusion (HAI) delivers localized high-dose floxuridine directly to liver tumors through an implanted pump. While patients are undergoing active treatment, the pump is refilled with chemotherapy alternating with saline every 2 weeks using a specialized noncoring needle. Numerous clinical scenarios influence the dosing of floxuridine, which do not conform to the usual dose modification schema for systemic chemotherapy. This article aims to provide practical clinical management solutions to overcome the common challenges faced by oncologists in the real-world management of HAI pump therapy.

Starting a successful hepatic artery infusion pump program: A practical guide.

Implementation of a successful hepatic artery infusion pump program requires numerous factors to be in place, and the lack of any of these may lead to program failure. First and foremost, hepatic artery infusion pump programs must have adequate surgical expertise in the complex technical aspects of hepatic artery infusion pump implantation and postoperative management. Most new hepatic artery infusion pump programs are initiated by a surgeon and led in conjunction with a medical oncologist. Medical oncology experience in floxuridine dosing is critical in maximizing the treatment doses and the number of cycles administered while avoiding biliary toxicity. This is facilitated by collaboration with an engaged pharmacy team. To have adequate patient volume for a successful program, internal and external stakeholders must have buy-in, including surgical and medical oncology colleagues unfamiliar with hepatic artery infusion pumps, colorectal surgery, and other referring providers. Programmatic support must be obtained from the hospital, cancer center, and department administration. Day-to-day pump access for chemotherapy and maintenance saline fills must be performed by appropriately trained infusion nurses to avoid complications. Nuclear and diagnostic radiology experience is key to identifying extrahepatic perfusion and hepatic artery infusion pump-specific complications. Additionally, skilled interventional radiologists and gastroenterologists are necessary to identify and treat rare complications rapidly. Finally, given the current rapid expansion of hepatic artery infusion pump programs, new programs must identify engaged mentors to help guide patient selection, navigate the nuanced issues that may arise, and provide advice in the case of complications. Although hepatic artery infusion pump dissemination outside of several major tertiary centers previously had stalled, establishing a successful and active hepatic artery infusion pump is feasible with appropriate training, mentorship, and thoughtful assembly of a dedicated multidisciplinary team.

Systemic exposure of floxuridine after hepatic arterial infusion pump chemotherapy with floxuridine in patients with resected colorectal liver metastases.

BACKGROUND: Floxuridine's high hepatic extraction ratio and short elimination half-life allows maximum liver exposure with minimal systemic side-effects. This study attempts to quantify the systemic exposure of floxuridine. METHODS: Patients undergoing continuous hepatic arterial infusion pump (HAIP) floxuridine after resection of colorectal liver metastases (CRLM) in two centres underwent six cycles of floxuridine at start dose 0.12 mg/kg/day. No concomitant systemic chemotherapy was administered. Peripheral venous blood samples were drawn during the first two cycles: pre-dose (only in the second cycle), 30 min, 1 h, 2 h, 7 h, and 15 days after floxuridine infusion. Foxuridine concentration in the residual pump reservoir was measured on day 15 of both cycles. A floxuridine assay with a lower boundary of detection of 0.250 ng/mL was developed. RESULTS: 265 blood samples were collected in the 25 patient included in this study. Floxuridine was mostly measurable at day 7 and day 15 (86 % and 88 % of patients respectively). The median dose corrected concentrations were 0.607 ng/mL [IQR: 0.472-0.747] for cycle 1 day 7, 0.579 ng/mL [IQR: 0.470-0.693] for cycle 1 day 15, 0.646 ng/mL [IQR: 0.463-0.8546] for cycle 2 day 7, and 0.534 ng/mL [IQR: 0.4257-0.7075] for cycle 2 day 15. One patient had remarkably high floxuridine concentrations reaching up to 44 ng/mL during the second cycle, without a clear explanation. The floxuridine concentration in the pump decreased by 14.7 % (range 0.5 %-37.8 %) over a period of 15 days (n = 18). CONCLUSION: Overall, negligible systemic concentrations of floxuridine were detected. However, remarkably increased levels were detected in one patient. Floxuridine concentration in the pump decreases over time.

Comparison of Hepatic Arterial Infusion Pump Chemotherapy vs Resection for Patients With Multifocal Intrahepatic Cholangiocarcinoma.

Importance: Intrahepatic cholangiocarcinoma (iCCA) is often multifocal (ie, satellites or intrahepatic metastases) at presentation. Objective: To compare the overall survival (OS) of patients with multifocal iCCA after hepatic arterial infusion pump (HAIP) floxuridine chemotherapy vs resection. Design, Setting, and Participants: In this cohort study, patients with histologically confirmed, multifocal iCCA were eligible. The HAIP group consisted of consecutive patients from a single center who underwent HAIP floxuridine chemotherapy for unresectable multifocal iCCA between January 1, 2001, and December 31, 2018. The resection group consisted of consecutive patients from 12 centers who underwent a curative-intent resection for multifocal iCCA between January 1, 1990, and December 31, 2017. Resectable metastatic disease to regional lymph nodes and previous systemic therapy were permitted. Patients with distant metastatic disease (ie, stage IV), those who underwent resection before starting HAIP floxuridine chemotherapy, and those who received a liver transplant were excluded. Data were analyzed on September 1, 2021. Main Outcomes and Measures: Overall survival in the 2 treatment groups was compared using the Kaplan-Meier method and log-rank test. Results: A total of 319 patients with multifocal iCCA were included: 141 in the HAIP group (median [IQR] age, 62 [53-70] years; 79 [56.0%] women) and 178 in the resection group (median [IQR] age, 60 [50-69] years; 91 [51.1%] men). The HAIP group was characterized by a higher percentage of bilobar disease (88.0% [n = 124] vs 34.3% [n = 61]), larger tumors (median, 8.4 cm vs 7.0 cm), and a higher proportion of patients with 4 or more lesions (66.7% [94] vs 24.2% [43]). Postoperative mortality after 30 days was 0.8% (95% CI, 0.0%-2.1%) in the HAIP group vs 6.2% (95% CI, 2.3%-9.7%) in the resection group (P = .01). The median OS for HAIP was 20.3 months vs 18.9 months for resection (P = .32). Five-year OS in patients with 2 or 3 lesions was 23.7% (95% CI, 12.3%-45.7%) in the HAIP group vs 25.7% (95% CI, 17.9%-37.0%) in the resection group. Five-year OS in patients with 4 or more lesions was 5.0% (95% CI, 1.7%-14.3%) in the HAIP group vs 6.8% (95% CI, 1.8%-25.3%) in the resection group. After adjustment for tumor diameter, number of tumors, and lymph node metastases, the hazard ratio of HAIP vs resection was 0.75 (95% CI, 0.55-1.03; P = .07). Conclusions and Relevance: This cohort study found that patients with multifocal iCCA had similar OS after HAIP floxuridine chemotherapy vs resection. Resection of multifocal intrahepatic cholangiocarcinoma needs to be considered carefully given the complication rate of major liver resection; HAIP floxuridine chemotherapy may be an effective alternative option.

Efficacies of FAEV and EMA/CO regimens as primary treatment for gestational trophoblastic neoplasia.

BACKGROUND: Guidelines recommend etoposide, methotrexate, actinomycin D (EMA)/cyclophosphamide, vincristine (CO) as first-line treatment for high-risk gestational trophoblastic neoplasia (GTN). However, the floxuridine, actinomycin D, etoposide and vincristine (FAEV) regimen is commonly used to treat these patients in China. We conducted a randomised controlled trial to compare the efficacies and toxicities of FAEV and EMA/CO. METHODS: Ninety-four patients with GTN were enrolled between May 2015 and April 2019 and randomly assigned to the FAEV or EMA/CO regimen. The rates of complete remission and relapse and the toxicities were compared in August 2021. RESULTS: Five patients were excluded from the analysis. There were 46 patients in the FAEV group and 43 patients in the EMA/CO group. The complete remission rates following primary treatment were 89.1% and 79.1% (P = 0.193), respectively. The relapse rates were 8.7% and 9.3% (P = 0.604). The apparent incidences of grade 4 myelosuppression were 60.9% and 32.6% (P = 0.008), respectively; however, they became both 32.6% (P = 0.996) after granulocyte colony-stimulating factor support. Other adverse reactions were similar in the two groups. No patient died of disease. CONCLUSION: FAEV has comparable efficacy and toxicity to EMA/CO as the primary treatment for high-risk GTN, and may thus be another first-line choice of chemotherapy. CLINICAL TRIAL REGISTRATION: chictr.org.cn: ChiCTR1800017423.

DNA-Damage-Response-Targeting Mitochondria-Activated Multifunctional Prodrug Strategy for Self-Defensive Tumor Therapy.

We report a novel multifunctional construct, M1, designed explicitly to target the DNA damage response in cancer cells. M1 contains both a floxuridine (FUDR) and protein phosphatase 2A (PP2A) inhibitor combined with a GSH-sensitive linker. Further conjugation of the triphenylphosphonium moiety allows M1 to undergo specific activation in the mitochondria, where mitochondria-mediated apoptosis is observed. Moreover, M1 has enormous effects on genomic DNA ascribed to FUDR's primary function of impeding DNA/RNA synthesis combined with diminishing PP2A-activated DNA repair pathways. Importantly, mechanistic studies highlight the PP2A obtrusion in FUDR/5-fluorouracil (5-FU) therapy and underscore the importance of its inhibition to harbor therapeutic potential. HCT116 cell xenograft-bearing mice that have a low response rate to 5-FU show a prominent effect with M1, emphasizing the importance of DNA damage response targeting strategies using tumor-specific microenvironment-activatable systems.

Aptamers Entirely Built from Therapeutic Nucleoside Analogues for Targeted Cancer Therapy.

Owing to the specific and high binding affinity of aptamers to their targets, aptamer-drug conjugates (ApDCs) have emerged as a promising drug delivery system for targeted cancer therapy. However, in a conventional ApDC, the aptamer segment usually just serves as a targeting moiety, and only a limited number of drug molecules are sequentially conjugated to the oligonucleotide, giving a relatively low drug loading capacity. To address this challenge, herein we employ four clinically approved nucleoside analogues, including clofarabine (Clo), ara-guanosine (AraG), gemcitabine (Ge), and floxuridine (FdU), to replace all natural nucleosides in aptamer sequences, generating a series of whole drug-constituted DNA-like oligomers that are termed drugtamers. Similar to their parent aptamers, the obtained drugtamers maintain the targeting capability and can specifically bind to the target receptors overexpressed on the cancer cell surface. With 100% drug loading ratio, active targeting capability, and enzyme-mediated release of active therapeutics, our drugtamers can strongly induce the apoptosis of cancer cells and inhibit the tumor progression, which enables a new potential for a better targeted cancer therapy.

A novel near-infrared theranostic probe for accurate cancer chemotherapy in vivo by a dual activation strategy.

A novel theranostic probe called CX-B-DF is constructed for precise chemotherapy guided by near-infrared (NIR) fluorescence imaging. Moreover, the theranostic probe shows high cytotoxicity to cancer cells under dual activation (H2O2 and TP), which causes the accuracy of drug release to be improved and the toxic side effects to be reduced.

Floxuridine Oligomers Activated under Hypoxic Environment.

Floxuridine oligomers are anticancer oligonucleotide drugs composed of a number of floxuridine residues. They show enhanced cytotoxicity per floxuridine monomer because the nuclease degradation of floxuridine oligomers directly releases highly active floxuridine monophosphate in cells. However, their clinical use is limited by the low selectivity against cancer cells. To address this limitation, we herein report floxuridine oligomer prodrugs that are active under hypoxia conditions, which is one of the distinguishing features of the microenvironment of all solid tumors. We designed and synthesized two types of floxuridine oligomer prodrugs that possess hypoxia-responsive moieties on nucleobases. The floxuridine oligomer prodrugs showed lower cytotoxicity under normoxia conditions (O2 = 20%), while the parent floxuridine oligomer showed similar anticancer effects under hypoxia conditions (O2 = 1%). The floxuridine oligomer prodrug enabled tumor growth suppression in live mice. This would be the first example demonstrating the conditional control of the medicinal efficacy of oligomerized nucleoside anticancer drugs.

Mechanism of acquired 5FU resistance and strategy for overcoming 5FU resistance focusing on 5FU metabolism in colon cancer cell lines.

Fluorouracil (5FU) is converted to its active metabolite fluoro­deoxyuridine monophosphate (FdUMP) through the orotate phosphoribosyl transferase (OPRT)­ribonucleotide reductase (RR) pathway and thymidine phosphatase (TP)­thymidine kinase (TK) pathway and inhibits thymidylate synthase (TS), leading to inhibition of thymidine monophosphate (dTMP) synthesis through a de novo pathway. We investigated the mechanism of 5FU resistance and strategies to overcome it by focusing on 5FU metabolism. Colon cancer cell lines SW48 and LS174T and 5FU­resistant cell lines SW48/5FUR and LS174T/5FUR were used. FdUMP amount was measured by western blotting. The FdUMP synthetic pathway was investigated by combining TP inhibitor (tipiracil hydrochloride; TPI) or RR inhibitor (hydroxyurea; HU) with 5FU. Drug cytotoxicity was observed by crystal violet staining assay. FdUMP was synthesized through the OPRT­RR pathway in SW48 cells but was scarcely synthesized through either the OPRT­RR or TP­TK pathway in SW48/5FUR cells. FdUMP amount in SW48/5FUR cells was reduced by 87% vs. SW48 cells. Expression levels of OPRT and TP were lower in SW48/5FUR when compared with these levels in the SW48 cells, indicating decreased synthesis of FdUMP­led 5FU resistance. These results indicated that fluoro­deoxyuridine (FdU) rather than 5FU promotes FdUMP synthesis and overcomes 5FU resistance. Contrastingly, FdUMP was synthesized through the OPRT­RR and TP­TK pathways in LS174T cells but mainly through the TP­TK pathway in LS174T/5FUR cells. FdUMP amount was similar in LS174T/5FUR vs. the LS174T cells. OPRT and RR expression was lower and TK expression was higher in LS174T/5FUR vs. the LS174T cells, indicating that dTMP synthesis increased through the salvage pathway, thus leading to 5FU resistance. LS174T/5FUR cells also showed cross­resistance to FdU and TS inhibitor, suggesting that nucleoside analogs such as trifluoro­thymidine should be used to overcome 5FU resistance in these cells. 5FU metabolism and mechanisms of 5FU resistance are different in each cell line. Both synthesized FdUMP amount and FdUMP sensitivity should be considered in 5FU­resistant cells.

Co-delivery of 5-fluorodeoxyuridine and doxorubicin via gold nanoparticle equipped with affibody-DNA hybrid strands for targeted synergistic chemotherapy of HER2 overexpressing breast cancer.

Combination chemotherapy is still of great importance as part of the standard clinical care for patients with HER2 positive breast cancer. As an attractive component, gold nanoparticles (AuNPs) have been extensively studied as biosafety nanomaterials, but they are rarely explored as drug nanocarriers for targeted co-delivery of multiple chemotherapeutics. Herein, a novel affibody-DNA hybrid strands modified AuNPs were fabricated for co-loading nucleoside analogue (5-fluorodeoxyuridine, FUdR) and anthracycline (doxorubicin, Dox). FUdRs were integrated into DNA hybrid strands decorated on AuNPs by DNA solid phase synthesis, and Dox molecules were intercalated into their duplex regions. Affibody molecules coupled to the DNA hybrid strands were distributed the surface of AuNPs, giving them targeting for HER2. The new dual-drug-containing affibody-DNA-AuNPs (Dox@affi-F/AuNPs) owned compact and stable spherical nanostructures, and precise drug loading. Cytotoxicity tests demonstrated that these nanoparticles caused a higher inhibition in HER2 overexpressing breast cancer cells, and showed better synergistic antitumor activity than simple mixture of the two drugs. The related mechanistic studies proved that Dox@affi-F/AuNPs achieved a remarkable combined antitumor activity of Dox and FUdR by promoting more cells to enter apoptosis pathway. Our work provided a nanomedicine platform for targeted co-delivery of nucleoside analog therapeutics and anthracycline anticancer drugs to achieve synergistic treatment of HER2+ cancer.

Anticancer Strategy Targeting Cell Death Regulators: Switching the Mechanism of Anticancer Floxuridine-Induced Cell Death from Necrosis to Apoptosis.

Cell death can be broadly characterized as either necrosis or apoptosis, depending on the morphological and biochemical features of the cell itself. We have previously reported that the treatment of mouse mammary carcinoma FM3A cells with the anticancer drug floxuridine (FUdR) induces necrosis in the original clone F28-7 but apoptosis in the variant F28-7-A. We have identified regulators, including heat shock protein 90, lamin-B1, cytokeratin-19, and activating transcription factor 3, of cell death mechanisms by using comprehensive gene and protein expression analyses and a phenotype-screening approach. We also observed that the individual inhibition or knockdown of the identified regulators in F28-7 results in a shift from necrotic to apoptotic morphology. Furthermore, we investigated microRNA (miRNA, miR) expression profiles in sister cell strains F28-7 and F28-7-A using miRNA microarray analyses. We found that several unique miRNAs, miR-351-5p and miR-743a-3p, were expressed at higher levels in F28-7-A than in F28-7. Higher expression of these miRNAs in F28-7 induced by transfecting miR mimics resulted in a switch in the mode of cell death from necrosis to apoptosis. Our findings suggest that the identified cell death regulators may play key roles in the decision of cell death mechanism: necrosis or apoptosis.

Affibody-Conjugated RALA Polymers Delivering Oligomeric 5-Fluorodeoxyuridine for Targeted Therapy of HER2 Overexpressing Gastric Cancer.

Affibody-conjugated RALA (affi-RA) are designed for delivering oligomeric 5-fluorodeoxyuridine (FUdR, metabolite of 5-FU) strand to raise the selectivity of 5-fluorouracil (5-FU), decrease its toxicity and improve its suboptimal therapeutic efficacy. The nanodrugs, FUdR@affi-RA, are spontaneously assembled by electrostatic interaction between positively charged affi-RA and negatively charged FUdR15 -strands (15 consecutive FUdR). FUdR@affi-RA exhibits excellent stability under simulated physiological conditions. Compared with free FUdR, FUdR@affi-RA shows excellent targeting and higher cytotoxicity in human epidermal growth factor receptor 2 (HER2) overexpressing gastric cancer N87 cells. Moreover, the anticancer mechanism studies reveal that FUdR@affi-RA enhances the expression and activity of apoptosis-associated proteins in the Bcl-2/Bax-caspase 8,9-caspase 3 apoptotic pathway induced by FUdR. This study indicates that the fusion vector, affi-RA, presents a promising delivery system platform for nucleoside analogue drugs and provides a new strategy for the development of therapeutics of cancer treatment.

Assessment of Hepatic Arterial Infusion of Floxuridine in Combination With Systemic Gemcitabine and Oxaliplatin in Patients With Unresectable Intrahepatic Cholangiocarcinoma: A Phase 2 Clinical Trial.

IMPORTANCE: Unresectable intrahepatic cholangiocarcinoma (IHC) carries a poor prognosis, with a median overall survival (OS) of 11 months. Hepatic arterial infusion (HAI) of high-dose chemotherapy may have potential benefit in these patients. OBJECTIVE: To evaluate clinical outcomes when HAI chemotherapy is combined with systemic chemotherapy in patients with unresectable IHC. DESIGN, SETTING, AND PARTICIPANTS: A single-institution, phase 2 clinical trial including 38 patients was conducted with HAI floxuridine plus systemic gemcitabine and oxaliplatin in patients with unresectable IHC at Memorial Sloan Kettering Cancer Center between May 20, 2013, and June 27, 2019. A confirmatory phase 1/2 study using the same therapy was conducted during the same time period at Washington University in St Louis. Patients with histologically confirmed, unresectable IHC were eligible. Resectable metastatic disease to regional lymph nodes and prior systemic therapy were permitted. Patients with distant metastatic disease were excluded. INTERVENTIONS: Hepatic arterial infusion of floxuridine and systemic administration of gemcitabine and oxaliplatin. MAIN OUTCOMES AND MEASURES: The primary outcome was progression-free survival (PFS) of 80% at 6 months. RESULTS: For the phase 2 clinical trial at Memorial Sloan Kettering Cancer Center, 42 patients with unresectable IHC were included and, of these, 38 patients were treated (13 [34%] men; median [range] age at diagnosis, 64 [39-81] years). The median follow-up was 30.5 months. Twenty-two patients (58%) achieved a partial radiographic response, and 32 patients (84%) achieved disease control at 6 months. Four patients had sufficient response to undergo resection, and 1 patient had a complete pathologic response. The median PFS was 11.8 months (1-sided 90% CI, 11.1) with a 6-month PFS rate of 84.1% (90% CI, 74.8%-infinity), thereby meeting the primary end point (6-month PFS rate, 80%). The median OS was 25.0 months (95% CI, 20.6-not reached), and the 1-year OS rate was 89.5% (95% CI, 80.2%-99.8%). Patients with resectable regional lymph nodes (18 [47%]) showed no difference in OS compared with patients with node-negative disease (24-month OS: lymph node negative: 60%; 95% CI, 40%-91% vs lymph node positive: 50%; 95% CI, 30%-83%; P = .66). Four patients (11%) had grade 4 toxic effects requiring removal from the study (1 portal hypertension, 2 gastroduodenal artery aneurysms, 1 infection in the pump pocket). Subgroup analysis showed significant improvement in survival in patients with IDH1/2 mutated tumors (2-year OS, 90%; 95% CI, 73%-99%) vs wild-type (2-year OS, 33%; 95% CI, 18%-63%) (P = .01). In the Washington University in St Louis confirmatory cohort, 9 patients (90%) achieved disease control at 6 months; the most common grade 3 toxic effect was elevated results of liver function tests, and median PFS was 12.8 months (1-sided 90% CI, 6.4). CONCLUSIONS AND RELEVANCE: Hepatic arterial infusion plus systemic chemotherapy appears to be highly active and tolerable in patients with unresectable IHC; further evaluation is warranted.

Two-in-One Chemogene Assembled from Drug-Integrated Antisense Oligonucleotides To Reverse Chemoresistance.

Combinatorial chemo and gene therapy provides a promising way to cure drug-resistant cancer, since the codelivered functional nucleic acids can regulate drug resistance genes, thus restoring sensitivity of the cells to chemotherapeutics. However, the dramatic chemical and physical differences between chemotherapeutics and nucleic acids greatly hinder the design and construction of an ideal drug delivery system (DDS) to achieve synergistic antitumor effects. Herein, we report a novel approach to synthesize a nanosized DDS using drug-integrated DNA with antisense sequences (termed "chemogene") to treat drug-resistant cancer. As a proof of concept, floxuridine (F), a typical nucleoside analog antitumor drug, was incorporated in the antisense sequence in the place of thymine (T) based on their structural similarity. After conjugation with polycaprolactone, a spherical nucleic acid (SNA)-like two-in-one chemogene can be self-assembled, which possesses the capabilities of rapid cell entry without the need for a transfection agent, efficient downregulation of drug resistance genes, and chronic release of chemotherapeutics for treating the drug-resistant tumors in both subcutaneous and orthotopic liver transplantation mouse models.

Age-dependent effects of floxuridine (FUdR) on senescent pathology and mortality in the nematode Caenorhabditis elegans.

Floxuridine (5'-fluorodeoxyuridine, FUdR) acts as an inhibitor of DNA replication by binding to thymidylate synthase and is widely used to treat colorectal cancer. FUdR is also frequently used in research on aging in C. elegans since by blocking reproduction it allows maintenance of synchronous nematode populations. Here we examine age-specific effects of exposure to 50 µM FUdR on pathology and mortality. We report that initiating exposure to FUdR at late development or early adulthood reduces lifespan but later initiation increases it. Moreover, earlier initiation leads to enhancement of senescent intestinal atrophy, but amelioration of several other senescent pathologies (pharyngeal degeneration and uterine tumors). These results provide further evidence of the complex effects of FUdR on aging in C. elegans, and therefore support the argue against its routine use in studies of nematode aging due to its possible confounding effects. However, they also illustrate how effects of FUdR on aging are interesting in their own right.

Floxuridine Homomeric Oligonucleotides "Hitchhike" with Albumin In†Situ for Cancer Chemotherapy.

Automated attachment of chemotherapeutic drugs to oligonucleotides through phosphoramidite chemistry and DNA synthesis has emerged as a powerful technology in constructing structure-defined and payload-tunable oligonucleotide-drug conjugates. In practice, however, in vivo delivery of these oligonucleotides remains a challenge. Inspired by the systemic transport of hydrophobic payloads by serum albumin in nature, we report the development of a lipid-conjugated floxuridine homomeric oligonucleotide (LFU20) that "hitchhikes" with endogenous serum albumin for cancer chemotherapy. Upon intravenous injection, LFU20 immediately inserts into the hydrophobic cave of albumin to form an LFU20/albumin complex, which accumulates in the tumor by the enhanced permeability and retention (EPR) effect and internalizes into the lysosomes of cancer cells. After degradation, cytotoxic floxuridine monophosphate is released to inhibit cell proliferation.

Lipophilic Prodrug of Floxuridine Loaded into Solid Lipid Nanoparticles: In Vitro Cytotoxicity Studies on Different Human Cancer Cell Lines.

Floxuridine is a very effective drug with high potency in the treatment of various tumors but its utility is limited by its low efficiency of cellular uptake. In order to improve the floxuridine efficiency of cellular uptake, lipophilic prodrug of floxuridine (3',5'-distearoyl-5-fluoro-2'-deoxyuridine) was synthetized and loaded into behenic acid nanoparticles produced by fatty acid coacervation technique. Generally, spherical shaped SLN with mean diameters below 300 nm were obtained. Distearoyl-floxuridine was loaded in SLN with high entrapment efficiency (from 70.8 to 82.8%). In Vitro cytotoxicity studies on different human cancer cell lines (M14, HT-29 and MDA-MB231) were performed in order to test the ability of distearoyl-floxuridine-SLN to inhibit the cancer cell growth. In MTT test distearoyl floxuridine SLN showed a greater efficacy than floxuridine on all cancer cell lines revealing an efficiency about 100 times higher. Also clonogenic assay showed a higher cytotoxicity of distearoyl-floxuridine-SLN compared to floxuridine but the difference between the formulations was only about 10 times. In conclusion, SLN proved to be a promising vehicle to increase the floxuridine efficacy in cancer therapy.