Liquid Chromatography–Mass Spectrometry Method for The Analysis of The Anti-Cancer Agent Capecitabine and Its Nucleoside Metabolites in Human Plasma

A reversed-phase high-performance liquid chromatography method with electrospray ionization and mass spectral detection is described for the determination of capecitabine, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine in human plasma with 5-chloro-2′-deoxyuridine as the internal standard. An on-line sample clean-up procedure allows dilution of the plasma sample with the initial mobile phase. The linear dynamic range is 0.0500–10.0 μg/ml for capecitabine, and 0.0500–25.0 μg/ml for the metabolites, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine, respectively. This method has been used to analyze plasma samples from patients receiving capecitabine in combination with oxaliplatin

Liquid Chromatography–Mass Spectrometry Method for The Analysis of The Anti-Cancer Agent Capecitabine and Its Nucleoside Metabolites in Human Plasma

A reversed-phase high-performance liquid chromatography method with electrospray ionization and mass spectral detection is described for the determination of capecitabine, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine in human plasma with 5-chloro-2′-deoxyuridine as the internal standard. An on-line sample clean-up procedure allows dilution of the plasma sample with the initial mobile phase. The linear dynamic range is 0.0500–10.0 μg/ml for capecitabine, and 0.0500–25.0 μg/ml for the metabolites, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine, respectively. This method has been used to analyze plasma samples from patients receiving capecitabine in combination with oxaliplatin

Measurement of the Anticancer Agent Gemcitabine and Its Deaminated Metabolite at Low Concentrations in Human Plasma by Liquid Chromatography-Mass Spectrometry

A liquid chromatography/mass spectrometry (LC-MS) method has been developed and validated for the determination of the anticancer agent gemcitabine (dFdC) and its metabolite 2′,2′-difluoro-2′-deoxyuridine (dFdU) in human plasma. An Oasis® HLB solid phase extraction cartridge was used for plasma sample preparation. Separation of the analytes was achieved with a YMC ODS-AQ (5 μm, 120 Å, mm) column. The initial composition of the mobile phase was 2% methanol/98% 5 mM ammonium acetate at pH 6.8 (v/v), and the flow rate was 0.2 ml/min. An isocratic gradient was used for 3 min, followed by a linear gradient over 4 min to 30% methanol/70% 5 mM ammonium acetate at pH 6.8. The gradient returned to the initial conditions over 2 min and remained there for 6 min. The retention times of dFdC, dFdU, and the internal standard 5′-deoxy-5-fluorouridine (5′-DFUR) were 11.46, 12.63, and 13.58 min. The mass spectrometer was operated under negative electrospray ionization conditions. Single-ion-monitoring (SIM) mode was used for analyte quantitation at m/z 262 for [dFdC–H]−, m/z 263 for [dFdU–H]−, and m/z 245 for [5′-DFUR–H]−. The average recoveries for dFdC, dFdU, and 5′-DFUR were 88.4, 84.6, and 99.3%, respectively. The linear calibration ranges were 5–1000 ng/ml for dFdC, and 5–5000 ng/ml for dFdU. The intra- and inter-assay precisions (%CV) were ≤3 and ≤7% at three concentration levels (50.0, 500, and 5000 ng/ml). The limits of quantitation (defined as 10 times of signal-to-noise ratio) were 3.16 ng/ml for dFdC, and 1.35 ng/ml for dFdU with 50-μl sample injections. This method has been used for measuring plasma concentrations of dFdC and dFdU in samples from adult cancer patients in a Phase I trial of weekly dFdC given as 150 (or lower) mg/(m2 24-h) infusion. The average plasma dFdC concentrations at 22- and 23-h into the infusion were 18.3 and 16.8 ng/ml at 150 and 100 mg/m2, respectively; the values for dFdU averaged 2950 and 1372 ng/ml

Measurement of the Anti-Cancer Agent Gemcitabine in Human Plasma by High-Performance Liquid Chromatography

A reversed-phase HPLC assay has been developed to determine the concentration of the anti-metabolite 2′,2′-difluorodeoxycytidine (gemcitabine, dFdC) in human plasma over the concentration range of 0.5–150 μM (0.13–39.44 μg/ml), and 2′,2′-difluorodeoxyuridine (dFdU), the deaminated, inactive metabolite, over the range of 1.0–227 μM (0.26–60 μg/ml). After the addition of 20 nmol 2′-fluorodeoxycytidine (FdC) as an internal standard, 0.5-ml samples of plasma were subjected to acetonitrile precipitation, followed by analysis using a gradient reversed-phase HPLC assay with UV detection. A Phenomenex Columbus™ C18 column, 5 μm, 150×4.6 mm, and a Waters C18, 4 μm, Nova-Pak Sentry guard column were used to achieve separation. FdC, dFdC and dFdU were monitored at 282, 269 and 258 nm, respectively, on a Waters 996 photodiode array detector. The mobile phase, run at a total flow-rate of 1.5 ml/min, was composed of two solvents: 50 mM ammonium acetate pH 5.0 in either 2% (solvent A) or 10% methanol (solvent B, v/v); 100% solvent A was run for 17 min, followed by a linear gradient to 100% solvent B over 14 min. FdC, dFdC and dFdU were resolved from endogenous compounds and had retention times of 13.6±0.5, 18.1±1.1 and 29.0±0.6 min, respectively. The assay was useful in measuring the plasma levels of both analytes in samples obtained from adult cancer patients participating in a Phase I trial of gemcitabine given as either a 1- or 2-h infusion weekly for 3 of 4 weeks

A Phase I and Pharmacologic Study of Weekly Gemcitabine in Combination with Infusional 5-fluorodeoxyuridine and Oral Calcium Leucovorin

Purpose: Since preclinical studies have shown more than additive cytotoxicity and DNA damage with the combination of gemcitabine and 5-fluoro-2′-deoxyuridine (FUDR), we studied this combination in a phase I trial. Methods: Gemcitabine alone was given in cycle 1 as a 24-h, 2-h or 1-h i.v. infusion weekly for 3 of 4 weeks; if tolerated, a 24-h i.v. infusion of FUDR was added with oral leucovorin. The cycle was aborted for grade 3 thrombocytopenia, grade 4 neutropenia, and grade 2 or worse nonhematologic toxicity. Results: During cycle 1, six of eight patients who received 150 or 100 mg/m2 over 24 h had dose-limiting neutropenia, thrombocytopenia, fatigue or mucositis. Six of seven patients treated with 1000 mg/m2 over 2 h required a gemcitabine dose reduction for cycle 2 (thrombocytopenia, neutropenia, fatigue). Of 25 assessable patients who received gemcitabine 1000 mg/m2 over 1 h, 7 did not complete cycle 1 due to thrombocytopenia (n = 6) or diarrhea (n = 1). Of 42 patients entered, 27 received at least one course of gemcitabine/FUDR (5-19.5 mg/m2 over 24 h) without appreciable toxicity. Due to a shortage of FUDR, the protocol was closed early. Gemcitabine plasma concentrations averaged 0.061 μM (24 h), 16.3 μM (2 h), and 31.9 μM (1 h). In 21 paired bone marrow mononuclear cell samples obtained before treatment and during FUDR infusion, thymidylate synthase ternary complex was only seen during FUDR infusion. Conclusions: Gemcitabine 100-150 mg/m2 over 24 h was poorly tolerated, whereas toxicity was acceptable with 800-1000 mg/m2 over 1 h. Inhibition of the target enzyme was demonstrated at all FUDR doses

NCCAM/NCI Phase 1 Study of Mistletoe Extract and Gemcitabine in Patients with Advanced Solid Tumors

Purpose. European Mistletoe (Viscum album L.) extracts (mistletoe) are commonly used for cancer treatment in Europe. This phase I study of gemcitabine (GEM) and mistletoe in advanced solid cancers (ASC) evaluated: (1) safety, toxicity, and maximum tolerated dose (MTD), (2) absolute neutrophil count (ANC) recovery, (3) formation of mistletoe lectin antibodies (ML ab), (4) cytokine plasma concentrations, (5) clinical response, and (6) pharmacokinetics of GEM. Methods. Design: increasing mistletoe and fixed GEM dose in stage I and increasing doses of GEM with a fixed dose of mistletoe in stage II. Dose limiting toxicities (DLT) were grade (G) 3 nonhematologic and G4 hematologic events; MTD was reached with 2 DLTs in one dosage level. Response in stage IV ASC was assessed with descriptive statistics. Statistical analyses examined clinical response/survival and ANC recovery. Results. DLTs were G4 neutropenia, G4 thrombocytopenia, G4 acute renal failure, and G3 cellulitis, attributed to mistletoe. GEM 1380 mg/m2 and mistletoe 250 mg combined were the MTD. Of 44 patients, 24 developed nonneutropenic fever and flu-like syndrome. GEM pharmacokinetics were unaffected by mistletoe. All patients developed ML3 IgG antibodies. ANC showed a trend to increase between baseline and cycle 2 in stage I dose escalation. 6% of patients showed partial response, 42% stable disease. Median survival was 200 days. Compliance with mistletoe injections was high. Conclusion. GEM plus mistletoe is well tolerated. No botanical/drug interactions were observed. Clinical response is similar to GEM alone

Disruption of FDPS/Rac1 Axis Radiosensitizes Pancreatic Ductal Adenocarcinoma by Attenuating DNA Damage Response and Immunosuppressive Signalling

BACKGROUND: Radiation therapy (RT) has a suboptimal effect in patients with pancreatic ductal adenocarcinoma (PDAC) due to intrinsic and acquired radioresistance (RR). Comprehensive bioinformatics and microarray analysis revealed that cholesterol biosynthesis (CBS) is involved in the RR of PDAC. We now tested the inhibition of the CBS pathway enzyme, farnesyl diphosphate synthase (FDPS), by zoledronic acid (Zol) to enhance radiation and activate immune cells. METHODS: We investigated the role of FDPS in PDAC RR using the following methods: in vitro cell-based assay, immunohistochemistry, immunofluorescence, immunoblot, cell-based cholesterol assay, RNA sequencing, tumouroids (KPC-murine and PDAC patient-derived), orthotopic models, and PDAC patient\u27s clinical study. FINDINGS: FDPS overexpression in PDAC tissues and cells (P \u3c 0.01 and P \u3c 0.05) is associated with poor RT response and survival (P = 0.024). CRISPR/Cas9 and pharmacological inhibition (Zol) of FDPS in human and mouse syngeneic PDAC cells in conjunction with RT conferred higher PDAC radiosensitivity in vitro (P \u3c 0.05, P \u3c 0.01, and P \u3c 0.001) and in vivo (P \u3c 0.05). Interestingly, murine (P = 0.01) and human (P = 0.0159) tumouroids treated with Zol+RT showed a significant growth reduction. Mechanistically, RNA-Seq analysis of the PDAC xenografts and patients-PBMCs revealed that Zol exerts radiosensitization by affecting Rac1 and Rho prenylation, thereby modulating DNA damage and radiation response signalling along with improved systemic immune cells activation. An ongoing phase I/II trial (NCT03073785) showed improved failure-free survival (FFS), enhanced immune cell activation, and decreased microenvironment-related genes upon Zol+RT treatment. INTERPRETATION: Our findings suggest that FDPS is a novel radiosensitization target for PDAC therapy. This study also provides a rationale to utilize Zol as a potential radiosensitizer and as an immunomodulator in PDAC and other cancers. FUNDING: National Institutes of Health (P50, P01, and R01)

Survey of oxaliplatin-associated neurotoxicity using an interview-based questionnaire in patients with metastatic colorectal cancer

BACKGROUND: New chemotherapy regimens for patients with colorectal cancer have improved survival, but at the cost of clinical toxicity. Oxaliplatin, an agent used in first-line therapy for metastatic colorectal cancer, causes acute and chronic neurotoxicity. This study was performed to carefully assess the incidence, type and duration of oxaliplatin neurotoxicity. METHODS: A detailed questionnaire was completed after each chemotherapy cycle for patients with metastatic colorectal cancer enrolled in a phase I trial of oxaliplatin and capecitabine. An oxaliplatin specific neurotoxicity scale was used to grade toxicity. RESULTS: Eighty-six adult patients with colorectal cancer were evaluated. Acute neuropathy symptoms included voice changes, visual alterations, pharyngo-laryngeal dysesthesia (lack of awareness of breathing); peri-oral or oral numbness, pain and symptoms due to muscle contraction (spasm, cramps, tremors). When the worst neurotoxicity per patient was considered, grade 1/2/3/4 dysesthesias and paresthesias were seen in 71/12/5/0 and 66/20/7/1 percent of patients. By cycles 3, 6, 9, and 12, oxaliplatin dose reduction or discontinuation was needed in 2.7%, 20%, 37.5% and 62.5% of patients. CONCLUSION: Oxaliplatin-associated acute neuropathy causes a variety of distressing, but transient, symptoms due to peripheral sensory and motor nerve hyperexcitability. Chronic neuropathy may be debilitating and often necessitates dose reductions or discontinuation of oxaliplatin. Patients should be warned of the possible spectrum of symptoms and re-assured about the transient nature of acute neurotoxicity. Ongoing studies are addressing the treatment and prophylaxis of oxaliplatin neurotoxicity

17β-Estradiol Enhances Breast Cancer Cell Motility and Invasion via Extra-Nuclear Activation of Actin-Binding Protein Ezrin

Estrogen promotes breast cancer metastasis. However, the detailed mechanism remains largely unknown. The actin binding protein ezrin is a key component in tumor metastasis and its over-expression is positively correlated to the poor outcome of breast cancer. In this study, we investigate the effects of 17β-estradiol (E2) on the activation of ezrin and its role in estrogen-dependent breast cancer cell movement. In T47-D breast cancer cells, E2 rapidly enhances ezrin phosphorylation at Thr567 in a time- and concentration-dependent manner. The signalling cascade implicated in this action involves estrogen receptor (ER) interaction with the non-receptor tyrosine kinase c-Src, which activates the phosphatidylinositol-3 kinase/Akt pathway and the small GTPase RhoA/Rho-associated kinase (ROCK-2) complex. E2 enhances the horizontal cell migration and invasion of T47-D breast cancer cells in three-dimensional matrices, which is reversed by transfection of cells with specific ezrin siRNAs. In conclusion, E2 promotes breast cancer cell movement and invasion by the activation of ezrin. These results provide novel insights into the effects of estrogen on breast cancer progression and highlight potential targets to treat endocrine-sensitive breast cancers

Measurement of the Anticancer Agent Gemcitabine and Its Deaminated Metabolite at Low Concentrations in Human Plasma by Liquid Chromatography-Mass Spectrometry

A liquid chromatography/mass spectrometry (LC-MS) method has been developed and validated for the determination of the anticancer agent gemcitabine (dFdC) and its metabolite 2′,2′-difluoro-2′-deoxyuridine (dFdU) in human plasma. An Oasis® HLB solid phase extraction cartridge was used for plasma sample preparation. Separation of the analytes was achieved with a YMC ODS-AQ (5 μm, 120 Å, mm) column. The initial composition of the mobile phase was 2% methanol/98% 5 mM ammonium acetate at pH 6.8 (v/v), and the flow rate was 0.2 ml/min. An isocratic gradient was used for 3 min, followed by a linear gradient over 4 min to 30% methanol/70% 5 mM ammonium acetate at pH 6.8. The gradient returned to the initial conditions over 2 min and remained there for 6 min. The retention times of dFdC, dFdU, and the internal standard 5′-deoxy-5-fluorouridine (5′-DFUR) were 11.46, 12.63, and 13.58 min. The mass spectrometer was operated under negative electrospray ionization conditions. Single-ion-monitoring (SIM) mode was used for analyte quantitation at m/z 262 for [dFdC–H]−, m/z 263 for [dFdU–H]−, and m/z 245 for [5′-DFUR–H]−. The average recoveries for dFdC, dFdU, and 5′-DFUR were 88.4, 84.6, and 99.3%, respectively. The linear calibration ranges were 5–1000 ng/ml for dFdC, and 5–5000 ng/ml for dFdU. The intra- and inter-assay precisions (%CV) were ≤3 and ≤7% at three concentration levels (50.0, 500, and 5000 ng/ml). The limits of quantitation (defined as 10 times of signal-to-noise ratio) were 3.16 ng/ml for dFdC, and 1.35 ng/ml for dFdU with 50-μl sample injections. This method has been used for measuring plasma concentrations of dFdC and dFdU in samples from adult cancer patients in a Phase I trial of weekly dFdC given as 150 (or lower) mg/(m2 24-h) infusion. The average plasma dFdC concentrations at 22- and 23-h into the infusion were 18.3 and 16.8 ng/ml at 150 and 100 mg/m2, respectively; the values for dFdU averaged 2950 and 1372 ng/ml