Search

Antibody-enzyme conjugate (AbE) has been widely studied for site-specific prodrug activation in tumors. The purpose of this study is to characterize the pharmacokinetics and tissue distribution of HuCC49DeltaCH2-beta-galactosidase conjugate. HuCC49DeltaCH2 and beta-galactosidase were chemically conjugated and injected into a LS 174T colon cancer xenograft model. A colorimetric assay was developed to quantify the HuCC49DeltaCH2-beta-galactosidase levels in plasma and tissues. The HuCC49DeltaCH2-beta-galactosidase conjugate distributed into tumor tissue as early as 6h with the tumor/blood ratio of 5. This favored distribution of conjugate activity in the tumor tissue which was maintained up to 4 days post conjugate injection, while the conjugate was cleared rapidly from blood and other normal tissues (heart, spleen, lung, liver, kidney and stomach). At a high dose of 3000 U/kg, HuCC49DeltaCH2-beta-galactosidase conjugate saturated the antigen binding sites and yielded decreased tumor/normal tissue ratios compared to 1500 U/kg. These data suggest that HuCC49DeltaCH2-beta-galactosidase specifically target to the tumors to increase tumor selectivity.

E7389 (eribulin mesylate, Halaven, Eisai) is a fully synthetic analog of the marine sponge natural product halichondrin B. It has been approved in US and more than 50 countries worldwide for treatment of advanced breast cancer. To improve the therapeutic index of E7389, a liposomal formulation of E7389, E7389-LF is under development. In this study, we characterized the pharmacokinetics of E7389-LF and E7389 (aqueous formulation) in mice and evaluated the anti-tumor activity of E7389-LF and E7389 in mouse xenograft model. In general the pharmacokinetics of E7389-LF was characterized by a small volume of distribution, slow clearance, and slow elimination in all liposomal formulations tested. Plasma AUC of E7389-LF was more than 600 fold larger than that of E7389 in tumor bearing mice. Tumor AUC of E7389-LF was also observed. Moreover, free E7389 (not liposome encapsulated and not protein bound) was measured in mouse plasma by ultracentrifugation method. The concentration ratio of E7389 in ultracentrifuged mouse plasma (UCM) vs E7389 in plasma after a 2 mg/kg i.v. of E7389 ranged from 54.19% to 65.41%, which was similar to the free fraction in the mouse plasma. The respective concentration ratio of E7389 in UCM vs E7389 in plasma after a 2 mg/kg i.v. of E7389-LF ranged from 0.07% to 0.59%, and the exposure, expressed as AUC, of UCM/plasma ratio was determined to be 0.2%. The free E7389 exposure, measured by UCM, after E7389-LF administration was about 1.5 fold of that after E7389 administration. Anti-tumor activity of E7389-LF and E7389 was evaluated in a human pharynx carcinoma, FaDu, xenograft model. E7389-LF showed dose-dependent anti-tumor effect with regression of tumors at 2.5 mg/kg dose, which was significantly better than that after E7389 administration in this model. These findings suggest that E7389-LF showed better anti-tumor activity than that of E7389 in human FaDu xenograft mouse model. Citation Format: Makoto Asano, Kenji Hyodo, Yanke Yu, Edgar Schuck, Junji Matsui, Hiroshi Ishihara, Hiroshi Kikuchi, Kenichi Nomoto. Characterization of the liposomal formulation of eribulin mesylate (E7389) in mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4543. doi:10.1158/1538-7445.AM2015-4543

Neuropathy arising from chemotherapy (CIPN) is a major clinical problem representing the dose-limiting side effect of many antineoplastic drugs. At their respective MTDs, we previously reported paclitaxel and ixabepilone produced more severe deficits in nerve conduction velocity, amplitude and degenerative changes in dorsal root ganglia (DRG) and sciatic nerve (SN) versus eribulin mesylate (Wozniak et al 2011). Similar trends for eribulin to cause less neuropathy have also been reported in the clinic (Cigler and Vadhat 2010, Jain and Cigler 2012, Vadhat et al 2013). The underlying reason for this differential effect remains elusive. Differences in tubulin binding may, in part, explain the differential effect (Perez et al 2009, Jordan et al 2005). Another potential explanation could reside in different pharmacokinetic (PK) and nervous tissue distribution of these agents. Toward this latter point, we conducted tissue distribution and pharmacokinetic studies following acute dosing of eribulin mesylate, paclitaxel and ixabepilone. We reported that while all three drugs rapidly cleared from plasma, they distributed into and cleared slowly (>3 days) from peripheral nervous system tissues (Wozniak et al 2014). We have now extended these studies to look out to 42 days following both acute and 2 week MTD-dosing paradigms evaluating drug pharmacokinetics in plasma, DRG and SN as well as pharmacodynamic measurements of nerve conduction and amplitude. We found plasma levels of eribulin mesylate and paclitaxel rapidly declined over 24h after infusion. In contrast, the levels of eribulin mesylate and paclitaxel persisted at above quantification levels (ranging from 5-10 ng/g) for 7 to 14 days post cessation of 2 week MTD dosing. Eribulin mesylate consistently showed greater distribution into DRG and SN over paclitaxel. When comparing the induced nerve conduction deficits, we found paclitaxel and eribulin mesylate caused reduction of nerve conduction parameters similar to our previous studies, most notably in caudal nerve amplitude (by 80.5% and 54.9% respectively). However these deficits, which were sustained for up to several weeks after cessation of dosing, were more severe with paclitaxel. The findings demonstrate that despite eribulin mesylate showing higher nervous tissue distribution than paclitaxel, eribulin mesylate caused less neurotoxicity as evidenced by milder reductions in nerve conduction and amplitude. This work was financially supported by Eisai. Citation Format: Krystyna Wozniak, Ying Wu, Bruce A. Littlefield, Kenichi Nomoto, Christopher DesJardins, Yanke Yu, George Lai, Larisa Reyderman, Barbara S. Slusher. Pharmacokinetics and pharmacodynamic analysis of eribulin mesylate and paclitaxel in mouse. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4503. doi:10.1158/1538-7445.AM2015-4503

It has been reported that the phosphorylated form of histone variant H2AX (gammaH2AX) plays an important role in the recruitment of DNA repair and checkpoint proteins to sites of DNA damage, particularly at double strand breaks (DSBs). Using gammaH2AX foci formation as an indicator for DNA damage, several chemicals/stress factors were chosen to assess their ability to induce gammaH2AX foci in a 24h time frame in a human amnion FL cell line. Two direct-acting genotoxins, methyl methanesulfonate (MMS) and N-ethyl-N-nitrosourea (ENU), can induce gammaH2AX foci formation in a time- and dose-dependent manner. Similarly, an indirect-acting genotoxin, benzo[a]pyrene (BP), also induced the formation of gammaH2AX foci in a time- and dose-dependent manner. Another indirect genotoxin, 2-acetyl-aminofluorene (AAF), did not induce gammaH2AX foci formation in FL cells; however, AAF can induce gammaH2AX foci formation in Chinese hamster CHL cells. Neutral comet assays also revealed the induction of DNA strand breaks by these agents. In contrast, epigenetic carcinogens azathioprine and cyclosporine A, as well as non-carcinogen dimethyl sulfoxide, did not induce gammaH2AX foci formation in FL cells. In addition, heat shock and hypertonic saline did not induce gammaH2AX foci. Cell survival analyses indicated that the induction of gammaH2AX is not correlated with the cytotoxic effects of these agents/factors. Taken together, these results suggest that gammaH2AX foci formation could be used for evaluating DNA damage; however, the different cell types used may play an important role in determining gammaH2AX foci formation induced by a specific agent.

SBA-16 silica with intact surface hydroxyl groups was quickly obtained (5 min) via a fast-microwave-assisted method, and further adopted as an efficient template for the synthesis of three-dimensional (3D) ordered mesoporous CuOx–CeO2 catalysts (htpCCx) through a simple and reproducible host–guest interaction. XRD, XPS, H2-TPR, and Raman results reveal that many of the Cu2+ ions in htpCCx are incorporated into the CeO2 lattice, leading to the formation of a CuxCe1−xO2−δ solid solution, which produces a large number of oxygen vacancies and enhances the reducibility of the metal. The interaction of Cu and Ce is essential to the reaction as it maintains the Cu2+/Cu1+ and Ce4+/Ce3+ redox couples. The catalyst has a 3D mesostructure and possesses remarkably enhanced low-temperature activity for the combustion of epichlorohydrin. HtpCC20 has been identified as the most powerful catalyst for this reaction, with the reaction rate at 165 °C being about 6.3 and 33.3 times higher than those of catalysts synthesized using conventional incipient impregnation and thermal combustion methods, respectively. Furthermore, htpCC20 shows superior CO2 selectivity (>99%) and stability (no deactivation occurs after 50 h reaction). It is believed that the dispersion of the active phase, density of surface active oxygen, and low-temperature reducibility are the dominant factors governing the catalytic performance.

Sulforaphane, a Dietary Component of Broccoli/Broccoli Sprouts, Inhibits Breast Cancer Stem Cells The existence of cancer stem cells (CSCs) in breast cancer has profound implications for cancer prevention. The purpose of this study was to evaluate sulforaphane, a naturally occurring dietary compound from broccoli/broccoli sprouts, for its efficacy to inhibit breast CSCs as well as to elucidate the potential mechanisms of its effect. Aldefluor and mammosphere formation assays were used to assess the effect of sulforaphane on breast CSCs in vitro. A NOD/SCID xenograft model was employed to determine the efficacy of sulforaphane in targeting breast CSCs in vivo. The potential mechanism of sulforaphane was investigated utilizing Western blotting and β-catenin reporter assays. The results showed that sulforaphane (1∼5 µM) decreased aldehyde dehydrogenase (ALDH)-positive cell population by 65%∼80% in human breast cancer cell line (P < 0.01), and reduced the size and number of primary mammospheres by 8∼125-fold and 50%∼75% (P < 0.01), respectively. Daily injection with 50 mg/kg sulforaphane for two weeks reduced ALDH-positive cells by more than 50% in tumors (P = 0.003). Furthermore, sulforaphane eliminated breast CSCs in vivo, thereby abrogating tumor re-growth in secondary mice (P < 0.01). Western blotting showed that sulforaphane down-regulated the Wnt/β-catenin self-renewal pathway. These data suggest that sulforaphane targets breast CSCs through the down-regulation of the Wnt/β-catenin pathway as a potential mechanism. These findings provide a scientific rationale for use of sulforaphane and potentially broccoli/broccoli sprout dietary interventions for breast cancer chemoprevention. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4271.

The small heat shock protein 27 (Hsp27) is a molecular chaperone that is involved in a variety of cellular functions in cancer cells. The purpose of this research is to study the function of Hsp27 in metastasis of head and neck squamous cancer cells. The expression of Hsp27 in primary and metastatic head and neck cancer cells was determined using real-time PCR and western blotting. The siRNA knockdown of Hsp27 was performed in metastatic head and neck cancer cells using in vitro transfection. The proliferation of the primary and metastatic head and neck cancer cells were evaluated using MTS proliferation assay. The metastatic potential was determined using both migration assay and invasion assay in metastatic head and neck cancer cells after siRNA silencing of Hsp27. MTS proliferation showed that both primary (UM-SCC-22A) and metastatic (UM-SCC-22B) head and neck cancer cells have similar proliferation rate from 24-48 hrs. However, the metastatic head and neck cancer cells (UM-SCC-22B) showed more than 2-fold migration ability and more than 3-fold invasion ability than primary head and neck cancer cells (UM-SCC-22A). Real-time PCR demonstrated that Hsp27 mRNA is 22-fold higher in metastatic UM-SCC-22B than primary UM-SCC-22A. Similarly, Western blotting exhibited that primary UM-SCC-22A did not show any detectable levels of Hsp27, while metastatic UM-SCC-22B showed significant high levels (> 40-fold) of Hsp27. siRNA of Hsp27 knocked down expression of Hsp27 by more than 5-fold in mRNA level and 23-fold in protein levels in metastatic head and neck cancer cells UM-SCC-22B. Furthermore, siRNA knockdown of Hsp27 decreased metastasis of UM-SCC-22B by more than 50% in cell invasion assay. These data suggest that Hsp27 may regulate metastatic potential of head and neck squamous cancer cells. Silencing Hsp27 may decrease metastatic potential of head and neck squamous cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3392.

The purpose of this study is to investigate Hsp90/Cdc37 interaction and identify residues critical for the interaction using real-time luciferase complementation imaging and computational modeling. Molecular imaging using a split Renilla luciferase fragment complementation (SRL-FC) was established to monitor real-time Hsp90/Cdc37interactions in living cells. Computational modeling and molecular dynamics simulations were used to evaluate the interaction interface of Hsp90/Cdc37 complex and critical residues in the interaction interface were identified for mutagenesis. Western Blotting and co-immunoprecipitation were used to determine protein expression and complex formation. The molecular imaging in living cells showed that Hsp90 and Cdc37 helped the complementation of N-terminus of Renilla luciferase (fused with Hsp90; N-RL-Hsp90) and C-terminus of Renilla luciferase (fused with Cdc37, Cdc37-C-RL) with 170-fold higher luciferase activity than controls without Hsp90/Cdc37. This suggests that the SRL-FC is sensitive and specific to monitor the interaction of full length human Hsp90 and Cdc37. Molecular dynamics simulations revealed that the interface was constituted by a series of residues interacting through hydrophobic or polar interactions. Mutagenesis confirmed that mutations in Hsp90 (A121N, Q133A, F134A) and mutations in Cdc37 (M164K, R167A) led to the loss of complementation of N-RL-Hsp90 and Cdc37-C-RL (5 to 10-fold lower luciferase activity compared to wild-type), indicating these residues are critical in Hsp90/Cdc37 interactions. In comparison, mutations in Hsp90 (E47A, S113A) and mutations in Cdc37 (A204E) only decreased 50% of the complementation of N-RL-Hsp90 and Cdc37-C-RL, which suggests that these residues contribute less to Hsp90/Cdc37 interaction. In contrast, mutations of Hsp90 (R46A, S50A) and mutation in Cdc37 (L165H) did not change the complementation of N-RL-Hsp90 and Cdc37-C-RL, indicating that these residues did not contribute to Hsp90/Cdc37 interaction. The data suggests that molecular imaging using split Renilla luciferase fragment complementation (SRL-FC) can be used to identify the critical residues in Hsp90/Cdc37 interaction. Although Hsp90/Cdc37 interactions are through both hydrophobic and polar interactions, mutation in a single amino acid residue, including Ala121, Gln133, Phe134 in human Hsp90 and Met164, Arg167 in human Cdc37, is sufficient to disrupt Hsp90/Cdc37 interaction. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2672.

Purpose. The two purposes of this study were evaluating preclinical pharmacokinetics of MI-219 and predicting clearance (CL) and volume of distribution at steady-state (Vdss) of MI-219 in humans. Methods. Pharmacokinetic studies were conducted on mice, rats, dogs, and monkeys. Human CL of MI-219 was predicted using allometric scaling (SA), multi-exponential allometric scaling (ME), rule of exponents (RoE), single species scaling, two-term power equation (TTPE), physiologically based in vitro-in vivo extrapolation (IVIVE), and fu corrected intercept method (FCIM). In vitro assays were conducted to determine in vitro intrinsic CL, protein binding, and blood-plasma partition coefficients. To estimate half-life of MI-219, plasma concentration–time profile in humans was predicted using kallynochron and apolysichron time transformation (Dedrick plots) and normalization with MRT and Vdss (Wajima’s method). In addition, simultaneous interspecies scaling of CL, Vdss and concentration–time profile were performed by using Nonlinear Mixed Effects Modeling (NONMEM). Results. Preclinical studies showed that the elimination of MI-219 was mainly through metabolism. The validation using observed monkey CL and Vdss showed that MA, IVIVE and Oie-Tozer methods were accurately than the other methods. Human CL of MI-219 predicted by ME and IVIVE was between 0.237-0.342 L*h-1*kg-1. Human Vdss predicted by Oie-Tozer method and allometric scaling of unbound volume of distribution of tissues (VT/fuT) method was between 0.93-1.40 L*kg-1. Superimposition of rat, monkey and dog data was observed in Dedrick plots and Wajima’s transformations. Conclusions. The predicted human pharmacokinetics is useful for the design of first-in-human study. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.