Tumor Tissue Concentrations Research Articles

Quantitative Determination of Erlotinib And O -Desmethyl Erlotinib in Human Edta Plasma And Lung Tumor Tissue

To increase knowledge about lung tumor tissue levels of erlotinib and its primary active metabolite, and about erlotinib plasma levels in intercalated dosing schedules, a sensitive and accurate method for determination of erlotinib and O-desmethyl erlotinib (OSI-420) in human plasma and lung tumor tissue has been developed. A method with HPLC-MS/MS was validated over a linear range from 5 to 2500 ng/ml in plasma and from 5.0 to 500 ng/ml for lung tumor tissue homogenate (50-5000 ng/g for lung tumor). Calibration curves in plasma were used to quantify analytes in lung tumor tissue homogenate. Lung tumor tissue of 15 patients has been collected and analyzed with the presented method. This method has been successfully validated and applied to determine plasma and lung tumor tissue concentrations of erlotinib and O-desmethyl erlotinib in patients with non-small-cell lung cancer.

Comparison of Conventional Chemotherapy, Stealth Liposomes and Temperature-Sensitive Liposomes in a Mathematical Model

Various liposomal drug carriers have been developed to overcome short plasma half-life and toxicity related side effects of chemotherapeutic agents. We developed a mathematical model to compare different liposome formulations of doxorubicin (DOX): conventional chemotherapy (Free-DOX), Stealth liposomes (Stealth-DOX), temperature sensitive liposomes (TSL) with intra-vascular triggered release (TSL-i), and TSL with extra-vascular triggered release (TSL-e). All formulations were administered as bolus at a dose of 9 mg/kg. For TSL, we assumed locally triggered release due to hyperthermia for 30 min. Drug concentrations were determined in systemic plasma, aggregate body tissue, cardiac tissue, tumor plasma, tumor interstitial space, and tumor cells. All compartments were assumed perfectly mixed, and represented by ordinary differential equations. Contribution of liposomal extravasation was negligible in the case of TSL-i, but was the major delivery mechanism for Stealth-DOX and for TSL-e. The dominant delivery mechanism for TSL-i was release within the tumor plasma compartment with subsequent tissue- and cell uptake of released DOX. Maximum intracellular tumor drug concentrations for Free-DOX, Stealth-DOX, TSL-i, and TSL-e were 3.4, 0.4, 100.6, and 15.9 µg/g, respectively. TSL-i and TSL-e allowed for high local tumor drug concentrations with reduced systemic exposure compared to Free-DOX. While Stealth-DOX resulted in high tumor tissue concentrations compared to Free-DOX, only a small fraction was bioavailable, resulting in little cellular uptake. Consistent with clinical data, Stealth-DOX resulted in similar tumor intracellular concentrations as Free-DOX, but with reduced systemic exposure. Optimal release time constants for maximum cellular uptake for Stealth-DOX, TSL-e, and TSL-i were 45 min, 11 min, and <3 s, respectively. Optimal release time constants were shorter for MDR cells, with ∼4 min for Stealth-DOX and for TSL-e. Tissue concentrations correlated well quantitatively with a prior in-vivo study. Mathematical models may thus allow optimization of drug delivery systems to achieve a better therapeutic index.

Association of alpha fetoprotein in hepatocellular carcinoma with activation of hepatic progenitor cells and patient prognosis

Objective To investigate the relationship of alpha fetoprotein(AFP) with activation of hepatic progenitor cells in hepatocellular carcinoma(HCC) and the prognosis of HCC patients.Methods The clinical data of 92 HCC patients who received curative hepatectomy were retrospectively analyzed.The patients included 76 males and 16 females,with a median age of 51(ranging 25-72) years.Expression of AFP and CK19 protein was immunohistochemically stained and quantified.Kaplan-Meier survival analysis was used to observe the influence of AFP expression on postoperative survival of patients.Cochran-armitage trend test was used to analyse the association of AFP expression with activation of progenitor cells(CK19 staining).Results Patients with high AFP expression had a significantly shorter survival than those with low AFP expression(P=0.021).The activation score of hepatic progenitor cells was positively correlated with serum AFP concentration(P=0.046) and AFP expression in tumor tissues(P0.001).Conclusion AFP expression in HCC tissue predicts a poor prognosis.AFP is closely associated with activation of hepatic progenitor cells.

Glutamate is associated with a higher risk of seizures in patients with gliomas

To investigate the relationship of glutamate and glutamate transporter expression in human gliomas and surrounding peritumoral brain to the presence of tumor-associated seizures (TAS). We studied a retrospective (group 1: 190 patients) and then a prospective (group 2: 98 patients) cohort of patients who underwent a craniotomy for a supratentorial glioma. Tumor and peritumor tissue specimens were assayed for glutamate concentration and expression of glial glutamate transporters. Differences between the seizure (TAS) and seizure-free (non-TAS) groups were compared. A total of 42% of patients had TAS, with 95% of seizures first occurring preoperatively. Clinical factors independently associated with risk of TAS were younger age, temporal lobe location, and tumors with oligodendroglial components. Molecular features in tumor specimens associated with TAS were higher glutamate concentrations, reduced EAAT2 expression, and increased system X(c)(-) expression. In group 2, these results were also replicated in the peritumor tissue. Logistic regression analysis identified raised glutamate concentrations in tumor and peritumor tissue, increased expression of peritumor system X(c)(-), younger age, temporal lobe location, and tumors with oligodendroglial components as independently predictive of preoperative seizures. Relative increased glutamate concentration in gliomas, and altered glutamate transporter expression, are associated with the presence of TAS and may play a mechanistic role in their pathogenesis.

Nanoparticles for Targeted Delivery of Active Agents against Tumor Cells

Cancer therapy may still be considered as one of the most challenging issues in pharmaceutical sciences. Various new technologies and molecules have been developed to meet the needs of this devastating disease, but there is a long way to go. One of the most important challenges is finding a drug molecule or drug delivery system which only influences the cancer cells. This has not been achieved so far even though a great deal of research has focused on this goal. Most of the cytotoxic agents used for cancer treatment are toxic in nature and not only have an effect on tumor cells, but also normal cells are damaged when exposed with them. As a result, patients may experience intensive side effects which may lead to an early termination in chemotherapy due to their severity. Targeting the cancer cells specifically and selectively seems to be the best solution for this obstacle. Targeting the cancer cells occurs via two different strategies: passive targeting and active targeting. The conventional approach used for cancer therapy may be considered a sort of passive targeting. Cytotoxic agents used for cancer treatment select the cancer cells due to their faster growth rate. Inevitably, normal fast growing cells and normal fast dividing cells may damage following conventional chemotherapy. In 1986, Matsumura and Maeda brought up a new concept in passive targeting called enhanced permeation and retention (EPR) effect which was widely used in many researches as an approach for targeting tumor cells. In this strategy, the drug delivery system benefits from defective vasculature, fenestrations, and poor lymphatic drainage in tumor tissues. Utilizing molecular targeting moieties is another strategy which is widely used in new researches for targeting tumor cells actively and diminishing chemotherapy side effects. This special issue will primarily address new approaches for passive and active targeted cancer therapy with a focus on nanoparticle formulations specially those ones that specifically and selectively target tumors. There is a peper which describes using a natural protein, atelocollagen for oligonucleotide delivery, and evaluating its biological function. The researchers found that when oligonucleotides were used concomitantly with atelocollagen, paracellular flux was enhanced, but when each of these two constituents of the formulation was used separately, no effect was observed. Another paper reviews poly(lactic-co-glycolic acid)- (PLGA-) based nanoparticles especially echogenic ones to enhance gene delivery. Ultrasound may be used to enhance localized gene delivery in tumors. On the other hand, nanoparticles themselves may utilize targeting mechanisms to enhance the targeting potential of the current system. Another paper describes microemulsions in the form of nanocarriers for passive tumor targeting. In this study, an experimental design layout was used to optimize the excipients selection for microemulsion nanocarriers. These nanocarriers possess the ability of solubilizing hydrophobic drugs and physical stability alongside with their capability of passive targeting. In another paper human serum albumin was used as a naturally occurring protein to create nanoparticles for enhanced drug delivery in breast cancer. Albumin-based nanoparticles were further cationized by polyethylenimine. It was shown that delivery efficacy was improved by passive EPR strategy. One of the papers also reviews carbon nanotubes for cancer therapy and designing drug delivery systems. Carbon nanotubes present a great canvas for surface engineering and creating novel targeted nanoparticles. Another paper presents glucan particles which actively target cancer cells. Glucan particles which benefit from β-glucan derived from the cell wall of Saccharomyces cerevisiae provide receptor-mediated uptake by phagocytic macrophage cells who express β-glucan receptors. Different types of nanoparticles were incorporated or surface bounded to these glucan particles to deliver doxorubicin to macrophages. Macrophages further migrate into solid tumors carrying the cytotoxic agent to the target tissues like a Trojan horse, while they are resistant to the effects of doxorubicin due to their nondividing differentiated nature. Another paper reviews noble metal nanoparticles with a wide variety of biomedical applications which are used for both therapeutic and diagnostic purposes. They also present facile surface chemistry and the possibility of functionalizing on their surfaces. Finally, in one of the papers, a lipoplatin formulation consisting of liposomal encapsulated cisplatin is reviewed. The purpose of this formulation is to become a substitute for the original cisplatin and has gained positive results in clinical trials. Lipoplatin gives 200-fold higher concentrations in tumor tissues in comparison with cisplatin once more because of the compromised endothelium of tumor tissues. To sum up, this special issue tries to provide the readers some insight about the targeted nanoparticles which are designed for cancer therapy both for small molecular drugs and gene delivery systems. Rassoul Dinarvand Paulo Cesar de Morais Antony D'Emanuele

Patupilone (Epothilone B) for Recurrent Glioblastoma: Clinical Outcome and Translational Analysis of a Single-Institution Phase I/II Trial

Background: Patients with glioblastoma (GBM) inevitably develop recurrent or progressive disease after initial multimodal treatment and have a median survival of 6–9 months from time of progression. To date, there is no accepted standard treatment for GBM relapse or progression. Patupilone (EPO906) is a novel natural microtubule-stabilizing cytotoxic agent that crosses the blood-brain barrier and has been found to have preclinical activity in glioma models. Methods: This is a single-institution, early-phase I/II trial of GBM patients with tumor progression who qualified for second surgery with the goal of evaluating efficacy and safety of the single-agent patupilone (10 mg/m², every 3 weeks). Patients received patupilone 1 week prior to second surgery and every 3 weeks thereafter until tumor progression or toxicity. Primary end points were progression-free survival (PFS) and overall survival (OS) at 6 months as well as patupilone concentration in tumor tissue. Secondary end points were toxicity, patupilone concentration in plasma and translational analyses for predictive biomarkers. Results: Nine patients with a mean age of 54.6 ± 8.6 years were recruited between June 2008 and April 2010. Median survival and 1-year OS after second surgery were 11 months (95% CI, 5–17 months) and 45% (95% CI, 14–76), respectively. Median PFS was 1.5 months (95% CI, 1.3–1.7 months) and PFS6 was 22% (95% CI, 0–46), with 2 patients remaining recurrence-free at 9.75 and 22 months. At the time of surgery, the concentration of patupilone in tumor tissue was 30 times higher than in the plasma. Tumor response was not predictable by the tested biomarkers. Treatment was generally well tolerated with no hematological, but cumulative, though reversible sensory neuropathy grade ≤3 was seen in 2 patients (22%) at 8 months and grade 4 diarrhea in the 2nd patient (11%). Non-patupilone-related peri-operative complications occurred in 2 patients resulting in discontinuation of patupilone therapy. There were no neurocognitive changes 3 months after surgery compared to baseline. Conclusions: In recurrent GBM, patupilone can be given safely pre- and postoperatively. The drug accumulates in the tumor tissue. The treatment results in long-term PFS in some patients. Patupilone represents a valuable novel compound which deserves further evaluation in combination with radiation therapy in patients with GBM.

Abstract 5643: CRLX301, a novel tumor-targeted taxane nanopharmaceutical

Abstract Docetaxel is one of the most commonly prescribed anticancer agents. While efficacious, the therapeutic benefits of docetaxel are often compromised by immunosuppression and neurotoxicity, incurring a discontinuation rate of over 25%. Cerulean has developed a novel class of tumor-targeted nanopharmaceuticals designed to enhance both efficacy and tolerability. CRLX301, a self-assembling docetaxel nanopharmaceutical, possesses significantly enhanced efficacy and improved pharmacokinetics compared to the parent drug. IND-enabling toxicity studies for CRLX301 are currently underway. Compared to docetaxel, CRLX301 showed a superior PK profile, with a significantly longer half-life and a &amp;gt;20-fold higher drug concentration in tumor tissue 7 days after a single administration. The improved PK and biodistribution of CRLX301 docetaxel translated into superior antitumor activity in murine syngeneic and human xenograft models. In the murine B16.F10 tumor model, median survival at the MTD exceeded 100 days for CRLX301 compared to 38 days for the parent drug docetaxel. CRLX301 also demonstrated superior efficacy over docetaxel in tumor models representative of other cancer types as well, including cure rates between 50 and 83% in xenograft models representing triple-negative breast and squamous non-small cell lung cancer tumors, compared to no cures for docetaxel. Further, in the human prostate xenograft tumor model DU-145, CRLX 301 achieved a 100% cure rate compared to a relatively poor cure rate of 25% with docetaxel, 146 days after three weekly doses at the MTD. In summary, CRLX301 represents a new and potent anticancer therapeutic that has the potential to be a best-in-class taxane. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5643. doi:1538-7445.AM2012-5643

The liposomal daunorubicin plus tamoxifen: improving the stability, uptake, and biodistribution of carriers

The synergistic effects of tamoxifen on the sensitivity of MCF-7 cells to daunorubicin have been reported. Whether the effects of daunorubicin on MCF-7/adr cells can be improved by tamoxifen in liposomes and how tamoxifen changes daunorubicin’s behavior in vivo remains unclear. The aim of this study was to investigate the effects of tamoxifen on the uptake and biodistribution of daunorubicin liposomes by breast-cancer–resistant MCF-7/adr cells in vitro and in vivo. The uptake of liposomes by MCF-7/adr cells in vitro studies was measured using flow cytometry and laser confocal microscopy. The biodistributions of carriers and free drugs were evaluated by DiR dye using in vivo imaging. Tamoxifen obviously enhanced the cellular uptake of liposomes by MCF-7/adr cells in time-dependent manners. According to the results from in vivo imaging analysis, the mean fluorescence intensity of DiR liposomes with tamoxifen in the tumor regions of MCF-7/adr tumor-bearing nude mice was much stronger than that of DiR liposomes alone (16,450 ± 1,331 versus 3,666 ± 321; n = 3). Pegylated liposomes elongated the existence of daunorubicin in the circulatory system and the enhanced permeability and retention effect enhanced its concentration in local tumor tissues, which may provide the precondition for tamoxifen further promoting the uptake by MCF-7/Adr cells in vivo. Using daunorubicin liposomes and tamoxifen together generates better biodistribution profiles in tumor tissue than using daunorubicin liposomes only, which contributes to improving the therapeutic effect of breast cancer treatment.

Quantification of retinoid concentrations in human serum and brain tumor tissues

Retinoic acid signaling is essential for central nervous system (CNS) differentiation and appears to be impaired in tumors. Thus far, there are no established methods to quantify relevant retinoids (all-trans-retinoic acid, 9-cis-retinoic acid, 13-cis retinoic acid, and retinol) in human brain tumors. We developed a single step extraction and quantification procedure for polar and apolar retinoids in normal tissue, lipid-rich brain tumor tissues, and serum. This quantification procedure is based on high performance liquid chromatography (HPLC) with diode-array detection (DAD) using all-trans-acitretin as an internal standard and extraction by liquid–liquid partition with ethyl acetate and borate buffer at pH 9. Recovery with this extraction procedure was higher than earlier (two-step) liquid–liquid extraction procedures based on hexane, NaOH, and HCl. The overall quantification procedure was validated according to Food and Drug Administration (FDA) guidelines and fulfilled all criteria of accuracy, precision, selectivity, recovery, and stability. The overall method accuracy varied between −5.6% and +5.4% for serum and −3.8% and +6.2% for tissues, and overall precision ranged from 3.1% to 6.9% for serum and 2.1% to 8.3% for tissues (%CV batch-to-batch). The lower limit of quantification for all compounds in tumor tissue (and serum) was 3.9ngg−1 (ngmL−1). Using this assay, photodegradation of the retinoids was evaluated and endogenous polar and apolar retinoids were quantified in sera and brain tumor tissues of patients and compared with serum and tonsil tissue concentrations of controls. It may thus serve as a suitable method for the characterization of retinoid uptake and metabolism in the respective compartments.

The combination of hyperthermia or chemotherapy with gimeracil for effective radiosensitization

5-chloro-2,4-dihydroxypyridine (gimeracil) is a component of the oral fluoropyrimidine derivative S-1. Gimeracil was originally added to S-1 to yield prolonged 5-fluorouracil (5-FU) concentrations in serum and tumor tissues by inhibiting dihydropyrimidine dehydrogenase, which degrades 5-FU. We previously demonstrated that gimeracil enhances the efficacy of radiotherapy through the suppression of homologous recombination (HR) in DNA double strand repair. The goal of this paper was to examine the effects of gimeracil on the sensitivity of anticancer drugs and hyperthermia in order to obtain effective radiosensitization. Various cell lines, including DLD 1 (human colon carcinoma cells) and cells deficient in HR or nonhomologous end-joining (NHEJ), were used in clonogenic assays. The survival of these cells after various treatments (e.g., drug treatment, heat treatment, and radiation) was determined based on their colony-forming ability. Gimeracil enhanced cell-killing effects of camptothecin (CPT), 5-FU, and hydroxyurea. Gimeracil sensitized effects of CPT or 5-FU to cells deficient in HR or NHEJ to a similar extent as in other cells (DLD1 and a parent cell), indicating that its sensitizing mechanisms may be different from inhibition of HR or NHEJ. Combination of gimeracil and CPT or 5-FU sensitized radiation more effectively than each modality alone. Gimeracil also enhanced heat sensitivity at 42°C or more. The degree of heat sensitization with gimeracil increased as the temperature increased, and the combination of gimeracil and heat-sensitized radiation was more effective than each modality alone. Gimeracil enhanced sensitivity of CPT, 5-FU, and hyperthermia. Combination of these modalities sensitized radiation more efficiently than each modality alone.

Rapid and Simple Analysis of &amp;lt;i&amp;gt;N&amp;lt;/i&amp;gt;-Aspartylchlor in E6 (Talaporfin) Using Fluorescence Microtiterplate and Its Application for Determination in Cells, Tissues and Blood

N-aspartylchlorin e6 (talaporfin) concentrations in cancer cells, mouse liver tissues, and human plasma specimens were determined with fluorescence microtiter plate analysis. Talaporfin standard curves were obtained in each of the sample specimens of cells, mouse tissues, or human plasma including serial concentration of talaporfin. The correlation co-efficiencies (r2) of talaporfin standard curves were 0.99-1.00, and the CV less than 5%. Talaporfin incorporation into cells of human breast cancer cell line MCF-7 after incubating with 25 μg/mL talaporfin for up to 24 h revealed that the t-max of the drug incorporation was approximately 5 h, and the maximum drug concentration incorporated was 25 μg/107 cells. Talaporfin incorporation into MCF-7 cells was significantly decreased in the presence of 3 μg/mL cyc-losporine (p < 0.05). Balb/c nu/nu mice implanted human cholangiocarcinoma NOZ cells in liver were administered intravenously 5mg/mouse of talaporfin, and the tissues of normal liver and tumor, as well as plasma specimens, were analyzed for talaporfin concentrations. The mean (SD) of talaporfin concentration in plasma after 30 min of administration was 41.6 (2.3) μg/mL, while the level decreased to undetectable concentrations 2 h after administration. In contrast, the talaporfin concentrations in normal and tumor tissues after 30 min of administration were 1.1-7.8 μg/g tissue, and the level slightly increased or was almost maintained for up to 2-4 h after administration. The heparinized blood of the healthy subjects was incubated with 25 μg/mL talaporfin for up to 24 h. The plasma talaporfin concentration did not significantly change during the incubation, and thus talaporfin appears not to be incorporated into the blood cells. We established rapid and simple analysis procedures of talaporfin in biological specimens using a fluorescence microtiter plate assay. Using this assay procedure, the unique pattern of talaporfin disposition and pharmacokinetics were revealed in human cancer cells, liver tissues of tumor bearing mice, and human blood.

Magnetic drug targeting in a rhabdomyosarcoma rat model using magnetite-dextran composite nanoparticle-bound mitoxantrone and 0.6 tesla extracorporeal magnets − sarcoma treatment in progress

Background: Magnetic drug targeting (MDT) is a new treatment principle for tumors. Passive MDT (pMDT) uses cytostatics coupled to ferromagnetic nanoparticles, whereas in active MDT (aMDT), extracorporeal magnets are additionally placed over the tumor area.Purpose: Mitoxantrone-magnetite-dextran composite particles were used to assess the distribution and effect of MDT.Methods: We conducted two trials with n = 60 rats transfected with R1H rhabdomyosarcoma cells. In the biodistribution trial (n = 36) mitoxantrone concentrations in tumor tissue versus plasma were measured after one or two dose administration for aMDT, pMDT, and uncoupled mitoxantrone. The dose/effect trial (n = 24) assessed change in tumor volume at day 1 and 7 days after administration of 4, 6, or 8 doses of mitoxantrone using aMDT.Results: Mitoxantrone-magnetite-dextran concentration in blood was significantly (p < 0.05) lower when using aMDT and as low as uncoupled mitoxantrone. Concentrations in tumor tissue were always significantly higher using MDT when compared to uncoupled mitoxantrone. Two doses resulted in drug accumulation inside the tumor. Tumor growth was significantly decreased with four doses using aMDT versus no treatment. Tumor size on day 8 versus day 1 was significantly (p < 0.05) reduced after administration of six doses of mitoxantrone-magnetite-dextran. No allergies/toxic reactions were observed.Conclusions: The MDT achieves higher levels of cytostatics in tumor tissue without increased systemic concentrations and succeeds in reducing tumor volume.

Increased Mean Corpuscular Volume of Erythrocytes during Capecitabine Treatment: A Simple Surrogate Marker for Clinical Response

Capecitabine, as all fluoropyrimidines, interferes with vitamin metabolism and may thus have an impact on hematopoiesis. It is metabolized to its active form 5-fluoruracil by the enzyme thymidine phosphorylase, which exists in higher concentrations in tumor tissue and liver than in normal tissues. In the study, we investigated the changes in mean corpuscular volume (MCV) of red blood cells and the possible correlation of these changes with the clinical outcome of capecitabine treatment in women with metastatic breast cancer. Data from 75 metastatic breast cancer patients were analyzed retrospectively. Capecitabine was used at a dose of 2500 mg/m² daily for 14 days of every 3-week period. Mean corpuscular volume of red blood cells and other parameters of complete blood count were recorded at the beginning of the treatment, in the ninth week, and periodically thereafter. Mean age was 51.5 ± 10.8 and 61.3% of the patients were premenopausal. Capecitabine was administered as the median 3rd line (min-max: 1-9) treatment and a median of 6 cycles (min-max: 1-24) for metastatic breast cancer. Median ΔMCV level (post-treatment values at ninth week - baseline) was 8. ΔMCV was ≥8 in 37 patients and <8 in 38 patients. The 35 of the 37 patients with ΔMCV level ≥8 and 25 of the 38 patients with ΔMCV level <8 had clinical benefit (complete response + partial response + stable disease) from capecitabine treatment (P = 0.02). However, the difference between progression-free survival of the patients with ΔMCV levels higher than 8 and those with ΔMCV levels lower than 8 according to Kaplan-Meier survival analysis was not statistically significant (6.7 and 4.3 months, respectively, P = 0.26). Additionally, median ΔMCV level was 9.1 (min-max: -2.4 to 24.9) among patients who had clinical benefit and 5.90 (min-max: -0.8 to 12.3) among nonresponders (P = 0.016). Capecitabine increases the mean corpuscular volume levels of red blood cells by a yet unidentified mechanism. Early increment of mean corpuscular volume levels is higher than 8, i.e. by the 9th week, might predict clinical benefit from the treatment.

Changes in the expression and subcellular distribution of galectin-3 in clear cell renal cell carcinoma

BackgroundClear cell renal cell carcinoma, a solid growing tumor, is the most common tumor in human kidney. Evaluating the usefulness of β-galactoside binding galectin-3 as a diagnostic marker for this type of cancer could open avenues for preventive and therapeutic strategies by employing specific inhibitors of the lectin. To study a putative correlation between the extent of galectin-3 and the development of clear cell renal cell carcinoma, we monitored the quantity and distribution of this lectin in tissue samples from 39 patients.MethodsGalectin-3 concentrations in normal, intermediate and tumor tissues were examined by immunofluorescence microscopy and on immunoblots with antibodies directed against galectin-3 and renal control proteins. The cell nuclei were isolated to determine quantities of galectin-3 that were transferred into this compartment in normal or tumor samples.ResultsImmunofluorescence data revealed a mosaic pattern of galectin-3 expression in collecting ducts and distal tubules of normal kidney. Galectin-3 expression was significantly increased in 79% of tumor samples as compared to normal tissues. Furthermore, we observed an increase in nuclear translocation of the lectin in tumor tissues.ConclusionsOur data indicate that changes in the cellular level of galectin-3 correlate with the development of clear cell renal cell carcinoma, which is in line with previously published data on this specific type of tumor. In most of these studies the lectin tends to be highly expressed in tumor tissues. Furthermore, this study suggests that the increase in the proportion of galectin-3 affects the balance from a cytosolic distribution towards translocation into the nucleus.

The Urokinase Plasminogen Activator System in Metastatic Papillary Thyroid Carcinoma: A Potential Therapeutic Target

Although distant metastases occur in a minority of papillary thyroid carcinoma (PTC) patients, their impact on disease course and survival rates is profound, with aggregate 10-yr survival rates of 40% (1). Limited treatment options further complicate management of metastatic PTC. Radioiodine (RAI) remains the standard of care for most distant metastases in PTC. Of particular concern, however, is the significant prevalence of PTC metastases unable to trap RAI; such metastases are termed RAI-refractory (RAIR). Because thyroid cancer loses differentiated features of normal thyroid tissue, one feature commonly lost is sodium iodide symporter expression, which is the entire basis for the use of RAI therapy in thyroid malignancies. This phenomenon can occur in a heterogeneous manner: in a given patient, RAI uptake can vary between individual metastases, and it can even vary within a metastasis at the cellular level.

Multidrug resistance reversal effect of DMC derived from buds of Cleistocalyx operculatus in human hepatocellular tumor xenograft model

Multidrug resistance (MDR) is a major obstacle in the chemotherapeutic treatment of many human cancers. 2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) isolated from the buds of Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae), was investigated for its reversal effects on cancer cell MDR. A human hepatocellular tumor xenograft model was established with the BEL-7402/5-FU cell line. Combined 5-fluorouracil (5-FU) and DMC (40 mg kg(-1) ) treatment significantly elevated tumor inhibition rate to 72.2%. DMC could also increase 5-FU concentrations in tumor tissues and increase caspase-3 activity. Also, combined therapy resulted in enhanced tumor apoptotic and reduced proliferative activities relative to 5-FU alone. Examining body weight and other signs of unwanted toxicity of the different treatment groups revealed no significant signs of adverse effects. All results suggested that DMC reverses 5-FU resistance, with a benign side effects profile.

Gimeracil, an inhibitor of dihydropyrimidine dehydrogenase, inhibits the early step in homologous recombination

Gimeracil (5-chloro-2, 4-dihydroxypyridine) is an inhibitor of dihydropyrimidine dehydrogenase (DPYD), which degrades pyrimidine including 5-fluorouracil in the blood. Gimeracil was originally added to an oral fluoropyrimidine derivative S-1 to yield prolonged 5-fluorouracil concentrations in serum and tumor tissues. We have already reported that gimeracil had radiosensitizing effects by partially inhibiting homologous recombination (HR) in the repair of DNA double strand breaks. We investigated the mechanisms of gimeracil radiosensitization. Comet assay and radiation-induced focus formation of various kinds of proteins involved in HR was carried out. siRNA for DPYD were transfected to HeLa cells to investigate the target protein for radiosensitization with gimeracil. SCneo assay was carried out to examine whether DPYD depletion by siRNA inhibited HR repair of DNA double strand breaks. Tail moments in neutral comet assay increased in gimeracil-treated cells. Gimeracil restrained the formation of foci of Rad51 and replication protein A (RPA), whereas it increased the number of foci of Nbs1, Mre11, Rad50, and FancD2. When HeLa cells were transfected with the DPYD siRNA before irradiation, the cells became more radiosensitive. The degree of radiosensitization by transfection of DPYD siRNA was similar to that of gimeracil. Gimeracil did not sensitize DPYD-depleted cells. Depletion of DPYD by siRNA significantly reduced the frequency of neopositive clones in SCneo assay. Gimeracil partially inhibits the early step in HR. It was found that DPYD is the target protein for radiosensitization by gimeracil. The inhibitors of DPYD, such as gimeracil, could enhance the efficacy of radiotherapy through partial suppression of HR-mediated DNA repair.

Absolute Quantification of [11C]docetaxel Kinetics in Lung Cancer Patients Using Positron Emission Tomography

Tumor resistance to docetaxel may be associated with reduced drug concentrations in tumor tissue. Positron emission tomography (PET) allows for quantification of radiolabeled docetaxel ([(11)C]docetaxel) kinetics and might be useful for predicting response to therapy. The primary objective was to evaluate the feasibility of quantitative [(11)C]docetaxel PET scans in lung cancer patients. The secondary objective was to investigate whether [(11)C]docetaxel kinetics were associated with tumor perfusion, tumor size, and dexamethasone administration. Thirty-four lung cancer patients underwent dynamic PET-computed tomography (CT) scans using [(11)C]docetaxel. Blood flow was measured using oxygen-15 labeled water. The first 24 patients were premedicated with dexamethasone. For quantification of [(11)C]docetaxel kinetics, the optimal tracer kinetic model was developed and a noninvasive procedure was validated. Reproducible quantification of [(11)C]docetaxel kinetics in tumors was possible using a noninvasive approach (image derived input function). Thirty-two lesions (size ≥4 cm(3)) were identified, having a variable net influx rate of [(11)C]docetaxel (range, 0.0023-0.0229 mL·cm(-3)·min(-1)). [(11)C]docetaxel uptake was highly related to tumor perfusion (Spearman's ρ = 0.815;P < 0.001), but not to tumor size (Spearman's ρ = -0.140; P = 0.446). Patients pretreated with dexamethasone showed lower [(11)C]docetaxel uptake in tumors (P = 0.013). Finally, in a subgroup of patients who subsequently received docetaxel therapy, relative high [(11)C]docetaxel uptake was related with improved tumor response. Quantification of [(11)C]docetaxel kinetics in lung cancer was feasible in a clinical setting. Variable [(11)C]docetaxel kinetics in tumors may reflect differential sensitivity to docetaxel therapy. Our findings warrant further studies investigating the predictive value of [(11)C]docetaxel uptake and the effects of comedication on [(11)C]docetaxel kinetics in tumors.

Abstract 5329A: Micro-CT enables microlocalization and quantification of Her2-targeted gold nanoparticles within tumor regions

Abstract Gold nanoparticles are of interest as potential in vivo diagnostic and therapeutic agents, as X-ray contrast agents, drug delivery vehicles and radiation enhancers. The aim of this study was to quantitatively determine their targeting and microlocalization in mouse tumor models after intravenous injection by using micro- CT. Gold nanoparticles (15 nm) were coated with polyethylene glycol and covalently coupled to anti-Her2 antibodies (Herceptin). In vitro, conjugates incubated with Her2+ (BT-474) and Her2- (MCF7) human breast cancer cells showed specific targeted binding with a Her2+ to Her2- gold ratio of 39.4± 2.7:1. Nude mice, simultaneously bearing subcutaneous Her2+ and Her2- human breast tumors in opposite thighs were prepared. Gold nanoparticles alone, conjugated to Herceptin or to a non-specific antibody were compared. After intravenous injection of the gold nanoparticles, gold concentrations were determined by atomic absorption spectroscopy. Microlocalization of gold was carried out by calibrated micro-CT, giving both the radiodensities and gold concentrations in tumor and non-tumor tissue. All gold nanoparticle constructs showed accumulation, predominantly at tumor peripheries. However, the Herceptin-gold nanoparticles showed the best specific uptake in their periphery (15.8± 1.7% injected dose g-1), 1.6-fold higher than Her2- tumors and 22-fold higher than surrounding muscle. Imaging readily enabled detection of small, 1.5-mm-thick tumors. In this pre-clinical study, antibody-targeted 15 nm gold nanoparticles showed preferential uptake in cognate tumors, but even untargeted gold nanoparticles enhanced the visibility of tumor peripheries and enabled detection of millimeter-sized tumors. Micro-CT enabled quantification within various regions of a tumor. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5329A. doi:10.1158/1538-7445.AM2011-5329A

Abstract 5306: 18F-EF5 microPET imaging of treatment response from a novel, hypoxia-selective cytotoxin SN30000 in a human lung cancer xenograft model

Abstract Introduction: SN30000 (CEN-209) is a structural analogue of the clinically tested hypoxic cell cytotoxin tirapazamine, with improved tumor penetration and increased hypoxic cell kill activity in vitro and in vivo. In this study, we investigated the use of the hypoxia PET imaging agent 18F-EF5 to measure changes in tumor hypoxia before and after treatment with SN30000 in a rat model of human non-small cell lung cancer (H460). Methods: Xenografts were established by subcutaneous injection of about 5 million H460 cells into the lower hind limb of NIH-RNu nude rats, and after 12-13 days the tumors were used for imaging experiments. Using two groups of animals we studied the changes in hypoxia at early time point (5-6 h) and at about 24 h after intraperitoneal administration of a single dose SN30000 (90 mg/kg body weight) or saline. Each group consisted of two control tumors (saline) and three SN30000 treated tumors. In both pre- and post-treatment scans, animals were scanned for 15-20 min at 2.5 h after i.v. injection 0.7-1.4 mCi of 18F-EF5. After reconstruction, PET images were analyzed by drawing regions of interest (ROI) covering whole tumor tissue and on contralateral leg muscle as background ROI. Standard uptake values (SUV) were calculated from the radioactivity concentration in both tumor and muscle tissue after normalization to the injection dose and body weight of the animal. Results: All tumors (n=10) showed tumor-to-muscle ratios (2.2 to 3.1) high enough to delineate the tumor from background activity. The SUV values in pre-treatment scans ranged from 0.43 to 0.79. No change in 18F-EF5 uptake was observed when animals were imaged at 5-6 h post-SN30000 therapy (mean SUV 0.59 ± 0.18 vs 0.59 ± 0.08 at baseline). However, tumors when imaged at 24 h after the treatment showed a decrease in tumor accumulation of 18F-EF5 by 19.7% to 54.6% when compared to pre-treatment scans (SUV 0.39 ± 0.12 vs. 0.63 ± 0.09 at baseline, p=0.06). Three out of four control tumors showed a slight increase in SUV in post-treatment scan compared to pre-treatment scan. Conclusions: The results from this study suggest that SN30000 may reduce hypoxia as measured by 18F-EF5 PET imaging at a later time point (1 day) rather than a few hours after treatment, and suggest potential use of 2-nitroimidazole-based PET imaging as an early response biomarker during clinical development of this compound. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5306. doi:10.1158/1538-7445.AM2011-5306