X-ray microfluorescence for biodistribution studies of nanomedicines.

Currently, the in vivo distribution of drugs is investigated by non-spatial quantitative techniques. With the emergence of personal therapies using nanomedicines, deeper investigations are required to precisely know the in vivo fate of entrapped drugs, especially to predict possible toxicity. Here, we assess the capabilities of SR-µXRF for i) detecting drugs into nanomedicines without adding any marker, ii) mapping their distribution into tissues and iii) locally quantifying the drugs loaded into nanomedicines. To prepare the nanomedicine model, we used the bioconjugate diamine(dichloro)platinum (SQ-CDD) developed in the TERNANOMED Grant Project. Nanomedicines were intravenously injected into a nude mice model bearing a pancreatic tumour (PANC-1). The X-ray microfluorescence experiments were performed on embeds tissue sections of kidney and tumor at 2h and 24h after nanoparticles injection. Data collection was performed on the micro-imaging beamline ID13 of the European Synchrotron Radiation Facility (ESRF). A quantitative study was performed by atomic absorption spectroscopy (AAS), allowing to compare the platinum concentrations with those measured by X-ray. This study shows that the synchrotron radiation-based µXRF analysis is sensitive enough to detect and map the distribution of a drug entrapped into nanomedicine. A quantitative local analysis is possible with a tissue element as reference, or semi-quantitatively if the tissue reference is not homogenous.

A Squalene-Based Nanomedicine for Oral Treatment of Colon Cancer.

Nanotechnology offers many possibilities to improve drug treatments, including with regard to drug pharmacology. The current study reports a simple approach to improve cisplatin efficacy in the treatment of colon cancer through the creation of orally administered squalenoylated nanoparticles loaded with cisplatin (SQ-CDDP NP). Cytotoxic effects of SQ-CDDP NP were assessed in human colonic cells and in mouse models of intestinal cancer. In cell culture, SQ-CDDP NP exhibited at least 10-fold greater cytotoxic potency compared with uncomplexed cisplatin, reflecting an enhancement in intracellular accumulation and DNA platination. Mechanistic investigations showed that SQ-CDDP NP stimulated ROS production, expression of heavy metal-inducible and stress-inducible genes, stress kinase cascades, and apoptosis. In ApcMin/+ mice, a model of intestinal tumorigenesis, oral administration of SQ-CDDP NP curtailed spontaneous tumor formation and azoxymethane-induced colon carcinogenesis with no apparent evidence of tissue toxicity. Our results offer preclinical validation of a nanocarrier formulation that can safely improve chemotherapeutic efficacy, address risks of drug resistance, and improve patient compliance by enabling oral administration. Cancer Res; 77(11); 2964-75. ©2017 AACR.

Antitumor activity of a rhenium (I)-diselenoether complex in experimental models of human breast cancer.

Rhenium (I)-diselenother (Re-diselenoether) is a water soluble metal-based compound, combining one atom of rhenium and two atoms of selenium. This compound has been reported to exhibit marked activities against several solid tumor cell lines. We now disclose an improved synthesis of this complex. The Re-diselenoether showed a potent inhibitory effect on MDA-MB231 cell division in vitro, which lasted when the complex was no longer present in the culture. Re-diselenoether induced a remarkable reduction of the volume of the primitive breast tumors and of the pulmonary metastases without clinical signs of toxicity, in mice-bearing a MDA-MB231 Luc+ tumor, orthotopically transplanted, after a daily oral administration at the dose of 10 mg/kg/d. Interestingly, an antagonism was observed when cisplatin was administered as a single i.p. injection 1 week after the end of the Re-diselenoether administration. In an effort to gain insight of the mechanisms of action of Re-diselenoether complex, interaction with 9-methylguanine as a nucleic acid base model was studied. We have shown that Re-diselenoether gave both mono- and bis-guanine Re adducts, the species assumed to be responsible for the DNA intrastrand lesions.

Uptake and efflux of rhenium in cells exposed to rhenium diseleno-ether and tissue distribution of rhenium and selenium after rhenium diseleno-ether treatment in mice.

UNLABELLED: We proposed a new water-soluble rhenium diseleno-ether compound (with one atom of Re and two atoms of Se) and investigated the uptake of Re into the nucleus of malignant cells in culture exposed to the compound for 48 h and its efflux from the nucleus after a post-exposure period of 48 h, as DNA is the main target of Re. We also studied the distribution of both Re and Se in the main organs after an oral administration of 10 or 40 mg/kg Re diseleno-ether to mice for four weeks, five days-a-week. MATERIALS AND METHODS: Re and Se concentrations were assayed by inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis was performed using the Wilcoxon signed-rank test, comparing two related groups. RESULTS: We observed that Re was well incorporated into the nucleus of malignant cells in the most sensitive cells MCF-7, derived from human breast cancer, and that there was no efflux of Re. In contrast, in MCF-7 resistant cells (MCF-7 Mdr and MCF-7 R), A549 and HeLa cells, there was significant efflux of Re from the nucleus after the wash-out period. In mice, an important and dose-dependent uptake of both Re and Se was observed in the liver, with lower concentrations in kidneys. The lowest concentrations were observed in blood, lung, spleen and bones. There was a significant increase of Re concentrations in the blood, liver and kidney in mice treated with Re diseleno-ether at the dose of 40 mg/kg/24 h versus those treated at the dose of 10 mg/kg/24 h. There was a significant increase of Se concentrations in all tissues with the dose of Re diseleno-ether of 10 mg/kg/24 h versus controls, and a significant increase in the liver in mice treated with dose of Re diseleno-ether of 40 mg/kg/24h versus those treated with 10 mg/kg/24 h. CONCLUSION: We are the first to demonstrate that a compound combining Re and Se in a single molecule, is able to deliver Re and Se to the organism via an oral route, for cancer treatment.

Differential pharmacological alleviation of oxaliplatin-induced hyperalgesia/allodynia at cephalic versus extra-cephalic level in rodents.

Previous data showed that neuropathic pain induced by mechanical lesion of peripheral nerves responds differently to alleviating drugs at cephalic versus extracephalic level. Because neuropathic pain evoked by anti-cancer drugs differs from that triggered by mechanical nerve lesion, we investigated whether differences between cephalic and extracephalic levels could also be characterized in rodents rendered neuropathic by treatment with the anti-cancer platinum derivative oxaliplatin. C57BL/6J mice received two injections and Sprague-Dawley rats three injections of oxaliplatin (10 mg/kg, i.p.) or its vehicle, with three days intervals. Supersensitivity to mechanical (von Frey filaments), cold (acetone drop) and chemical/inflammatory (formalin) stimulations was assessed in vibrissae and hindpaw territories. Transcripts of neuroinflammatory markers were quantified by real-time RT-qPCR in rat ganglia and central tissues. Oxaliplatin induced mechanical allodynia, cold hyperalgesia and chemical/inflammatory supersensitivity at both hindpaw and vibrissal levels in mice and rats. Acute treatment with gabapentin (30 mg/kg i.p.), morphine (3 mg/kg s.c.) or the 5-HT1A receptor agonist 8-OH-DPAT (0.16 mg/kg s.c.) significantly reduced oxaliplatin-induced supersensitivity in hindpaw but not vibrissal territory. In contrast, the antimigraine drugs naratriptan (0.1 mg/kg s.c.) and olcegepant (0.6 mg/kg i.v.) decreased oxaliplatin-induced supersensitivity in vibrissal territory only. Among the various markers investigated, only TRPA1 transcript was upregulated in ganglia of oxaliplatin-treated rats. These data showed that oxaliplatin induced supersensitivity to various stimuli in both cephalic and extra-cephalic territories in rodents. Regional differences in the efficacy of drugs to alleviate oxaliplatin-induced allodynia/hyperalgesia further support the idea that mechanisms underlying neuropathic pain have peculiarities at cephalic versus extra-cephalic level.

Acquired irinotecan resistance is accompanied by stable modifications of cell cycle dynamics independent of MSI status.

Irinotecan is a major anticancer agent specifically targeting DNA topoisomerase I. Its cytotoxicity is mediated via a two-step process involving accumulation of reversible DNA­topoisomerase I complexes associated with transient DNA single-strand breaks which subsequently are converted into permanent DNA double-strand breaks by the replication fork during S phase. Irinotecan may be selectively active for treatment of colorectal cancers that show microsatellite instability (MSI) due to deficiencies in mismatch repair enzymes, compared to tumors that are microsatellite stable but show chromosome instability (CIN). Although the clinical activity of irinotecan is principally limited by acquired drug resistance, surprisingly little is known about the influence of prolonged irinotecan exposure on the cell cycle dynamics. We have developed two colon cancer cell lines resistant to SN-38, the active metabolite of irinotecan, one derived from HT-29 (CIN), the other from HCT-116 (MSI). We here show that besides classical resistance mechanisms, SN-38 resistance is accompanied by an increased generation doubling time, a decreased S phase fraction and an increased G2 fraction in vitro as in tumor xenografts for both CIN and MSI models. As a consequence, SN-38-resistant cells and tumors show cross-resistance to the S-phase selective agent 5-fluorouracil. The resistance is accompanied by increased basal levels of γ-H2AX and phospho-Chk2 without notable changes in the levels of phospho-Chk1. Taken together, our results show that prolonged irinotecan exposure is accompanied by stable modifications of cell cycle dynamics which could have profound impact on tumor sensitivity to a wide range of antitumor agents and may influence tumor progression in patients.

Cell cycle arrest by oxaliplatin on cancer cells.

Oxaliplatin (L-OHP) is the only platinum compound to show activity in colorectal cancer. We evaluated the cytotoxicity of L-OHP on four human cancer cell lines and its influence on the cell cycle, when treated during long exposure (72 h) and different post-incubation times (24 or 72 h). We used a panel of cell lines: HT29 (colon cancer), MCF7 (breast cancer), Hela (uterine cervix) and A549 (lung adenocarcinoma). Inhibition concentration (IC)(50) was assessed by MTT assay. Cell cycle modifications were determined using dual parameter bromodeoxyuridine and propidium iodide. L-OHP yielded a superior cytotoxicity on HT29 and MCF7 relative to Hela and A549 after treatment, the post-incubations demonstrate that growth inhibition was irreversible for HT29 and Hela cell lines contrary to MCF7 and A549. The main effects of L-OHP are G2/M cell cycle arrest and transient S phase delay. Taken together, L-OHP treatment results on HT29, MCF7 and Hela, are in favor of lengthening the infusion duration to patients during further clinical trials.

Cell cycle arrest and apoptosis induced by oxaliplatin (L-OHP) on four human cancer cell lines.

BACKGROUND: The effects of oxaliplatin (L-OHP) on cell cycle and apoptosis were examined. MATERIALS AND METHODS: The HT29, MCF7, Hela and A549 cell lines were treated and dual parameter flow cytometry BrdU/PI was then performed to monitor cell cycle modifications. Annexin V-FITC and PI probes were used for the detection of apoptosis. RESULTS: The cells were treated for 3 h followed or not by 24 and 72 h of post-incubation. No changes were observed after 3 h of treatment, while after 24 h of post-incubation, all the cells except A549 were predominantly accumulated in the G2/M-phase; this accumulation was time-dependent. Apoptosis induction was late and moderate and was observed only after 12 h of treatment and 24 h of post-incubation. CONCLUSION: L-OHP induced cell cycle arrest and moderate apoptosis; these two activities were time-dependent. These findings warrant further investigation into the potential antitumour activity of L-OHP in MCF7 and Hela cells and in lengthening the infusion duration in order to achieve the acquired cellular modifications.

Comparative preclinical toxicology and pharmacology of isophosphoramide mustard, the active metabolite of ifosfamide.

BACKGROUND: Isophosphoramide mustard (IPM) is the cytotoxic alkylating metabolite of Ifosfamide (IFOS). IPM is being readied for a phase I clinical trial. In the present preclinical study, IPM was evaluated for usage in multidose intravenous (IV) infusion protocols. METHODS: Mice and dogs received IV IPM daily for 3 days. Single-day dosing-oral and IV-to mice, rats, and monkeys is also reviewed for comparison. Complete toxicology studies were completed in the mice and dogs. For mice, dogs and monkeys, IV pharmacokinetic studies were conducted and compared. RESULTS: For mice, the LD(10) for the 3-day IV schedule for IPM was calculated to be 119 mg/kg (with 95% confidence limits of 87-134 mg/kg) (combined sexes), and for adult male dogs the maximum tolerated dose (MTD) was 5 mg/kg. Pharmacokinetic studies in mice, dogs and monkeys were compared and projected to human dosing. For dogs that received 10 mg/kg of IPM, T(1/2beta) was 0.99 h, and clearance was constant (1.01 l/h/kg). IPM was detected from 0 h to 1.5 h after the 5 mg/kg dose and from 0 h to 2 h after the 10 mg/kg dose; none was detected after 2 h. The IV MTD in dogs was 5 mg/kg per day for 3 days. Renal tubular necrosis and bone marrow failure were the causes of death. Transient liver, renal and bone marrow toxicity and gastrointestinal dysfunction were seen at low doses (<5 mg/kg) in dogs. In mice (receiving 100 mg/kg IV) plasma concentrations disappeared in less than 1 h (T(1/2alpha) 2 min), with a clearance of 8.44 l/h/kg. For monkeys, the mean T(1/2) was 4.2 h. Median clearance was 1.65 l/h/kg and no IPM was detected 4 h after dosing. No potential IPM metabolites could be detected in any of the studies. In vitro, plasma protein bound 90% of IPM within 5 min of incubation. CONCLUSIONS: Predictions for human pharmacokinetic parameters and dosing are made from allometric analysis using the above three species. Data predicted an acceptable starting dose of 30 mg/m(2) with a clearance of 39.5 l/h, and a T(1/2) of 1 h 45 min for a 70-kg patient.

Oxaliplatin plus irinotecan and FU-FOL combination and pharmacokinetic analysis in advanced colorectal cancer patients.

This phase I-II trial was designed to assess the effect of irinotecan on oxaliplatin pharmacokinetics and to determine the MDT of both drugs when administered in combination. Treatment was repeated every 2 weeks. Pharmacokinetic studies were performed on cycle 1 and 2 to assess the best sequence and detect any interaction between the two drugs. Thirty-four patients with advanced colorectal cancer were enrolled; 28 of them (82%) had liver involvement. The main toxicities were neutropenia and delayed diarrhea; 5 patients (14%) experienced febrile neutropenia. Dose-limiting toxicity was experienced at levels 1/2/3/4/5 by 4/10, 1/6, 3/6, 3/8, and 3/4 patients, respectively. Fifteen patients responded (2 CR; 13 PR) for an ORR of 44%. No pharmacokinetic interactions between irinotecan and oxaliplatin were detected. The recommended dose for future phase II trials is oxaliplatin 85 mg/m and irinotecan 180 mg/m2 on day 1 combined with 5FU/leucovorin according to the de Gramont regimen at days 2 and 3. Twenty-nine percent of patients underwent secondary hepatectomy with curative intent, and two of them are long-term disease-free survivors. It would appear that the dose and schedule defined by this trial could be proposed as front-line therapy for advanced colorectal carcinoma to establish rapid disease control and to permit patients to proceed to surgery.