Role of Early PET/CT Imaging with 68Ga-PSMA in Staging and Restaging of Prostate Cancer.

Ga-68 Prostate-Specific Membrane Antigen PET/CT is a new tool for the assessment of prostate cancer. Standard imaging time is 60 minutes post injection of radiotracer. At 60 minutes, there is physiologic accumulation of radiotracer in the urinary bladder which may cause some lesions in its vicinity to be obscured. Our aim is to determine if early imaging at 3 minutes in addition to standard imaging at 60 minutes can improve the detection of PSMA-avid lesions. A retrospective review of 167 consecutive patients was conducted. Overall, 115 patients (68.9%) were ruled to have prostate cancer based on imaging as seen on early or standard PET/CT images. In 106/115 (64%), the lesions were detected on both early and standard imaging; in 8/115 (6.9%), the lesions were only detected on early imaging; in 1/115 (0.6%) the lesion was detected only on standard imaging. The addition of early imaging significantly improved the overall detection rate of PSMA-avid lesions (p = 0.039). The ratio of patients with lesions detected on early imaging but not on standard imaging in restaging group was 7/88 and was higher than that in staging group 1/79 (p = 0.043). We recommend early imaging in addition to the standard imaging in Ga-68 PSMA PET/CT, particularly in patients presenting for restaging of prostate cancer.

The "question-mark" MR anatomy of the cervico-thoracic ganglia complex: can it help to avoid mistaking it for a malignant lesion on 68Ga-PSMA-11 PET/MR?

Background Detectable uptake of 68Ga-PSMA-ligands in sympathetic ganglia may potentially lead to mistaking them for malignant lesions. Our aim was to investigate the anatomy of cervico-thoracic-ganglia-complex (CTG-C) in the MR part of multimodal 68Ga-PSMA-11 PET/MR imaging, in view of PET factors hindering its proper identification. Patients and methods In 106 patients, 212 sites of the CTG-C were retrospectively reviewed to assess the radiotracer uptake (SUVmax), size, shape, position, symmetry of location and visual uptake intensity. Asymmetry of PSMA-ligand uptake and increased uptake were regarded as risk factors of malignancy. Results In 66.0% left (L) and 53.8% right (R) CTG-C we noticed configurations, resembling the shape of an exclamation-mark, a question-mark, or its part (called "typical"). Tumor-like CTG-C shapes (oval, binodular or longitudinal) were detected in 28.3% L-CTG-C and in 40.6% R-CTG-C. When visual assessment of PET suggested malignancy, the recognition of "typical" shape of underlying CTG-C on MR generated a rise in the accuracy of their proper identification (from 34.4% to 75%, χ2(1) = 70.4; p < 0.001). Recognizing the shape of the CTG-C as "typical" in MR allowed us to classify as "not-suspicious" 61.9% of all CTG-C which were treated as "suspicious" after sole PET assessment. Conclusions The characteristic shape of cervico-thoracic-ganglia-complex (resembling a question-mark, or its part) helps in proper recognition of CTG-C on multimodal whole-body 68Ga-PSMA-ligand PET/MR imaging, when detectable uptake might lead to considering pathology.

68Ga/64Cu PSMA Bio-Distribution in Prostate Cancer Patients: Potential Pitfalls for Different Tracers.

BACKGROUND: 68Ga-PSMA is a widely useful PET/CT tracer for prostate cancer imaging. Being a transmembrane protein acting as a glutamate carboxypeptidase enzyme, PSMA is highly expressed in prostate cancer cells. PSMA can also be labeled with 64Cu, offering a longer half-life and different resolution imaging. Several studies documented bio-distribution and pitfalls of 68Ga-PSMA as well as of 64Cu- PSMA. No data are reported on differences between these two variants of PSMA. Our aim was to evaluate physiological distribution of these two tracers and to analyze false positive cases. METHODS: We examined tracer bio-distribution in prostate cancer patients with negative 68Ga-PSMA PET/CT (n=20) and negative 64Ga-PSMA PET/CT (n=10). A diagnostic pitfall for each tracer was documented. RESULT: Bio-distribution of both tracers was similar, with some differences due to renal excretion of 68Ga- PSMA and biliary excretion of 64Cu-PSMA. 68Ga-PSMA uptake was observed in sarcoidosis while 64Cu- PSMA uptake was recorded in pneumonitis. DISCUSSION: Both tracers may present similar bio-distribution in the human body, with similar uptake in exocrine glands and high intestinal uptake. Similarly to other tracers, false positive cases cannot be excluded in clinical practice. CONCLUSION: The knowledge of difference in bio-distribution between two tracers may help in interpretation of PET data. Diagnostic pitfalls can be documented, due to the possibility of PSMA uptake in inflammation. Our results are preliminary to future studies comparing diagnostic accuracies of 68Ga-PSMA and 64Cu-PSMA.

Effects of Linker Modification on Tumor-to-Kidney Contrast of 68Ga-Labeled PSMA-Targeted Imaging Probes.

68Ga-PSMA-11 is currently the most popular prostate-specific membrane antigen (PSMA) radioligand used in the clinic to detect prostate cancer and metastases. However, the high uptake of 68Ga-PSMA-11 in kidneys can create halo-artifacts resulting in lower detection sensitivity for lesions adjacent to the kidneys. In this study, we developed two 68Ga-labeled PSMA-targeted tracers, 68Ga-HTK01166 and 68Ga-HTK01167, based on 68Ga-PSMA-617 with the goal of improving tumor-to-kidney ratio compared to 68Ga-PSMA-11. The 2-naphthylalanine (2-Nal) in PSMA-617 was replaced with 2-indanylglycine (Igl) or 3,3-diphenylalanine (Dip) to synthesize HTK01166 and HTK01167, respectively. Binding affinities ( Ki) of Ga-PSMA-11, Ga-PSMA-617, Ga-HTK01166, and Ga-HTK01167 to PSMA were 3.13 ± 0.40, 1.23 ± 0.08, 5.74 ± 2.48, and 25.7 ± 9.84 nM, respectively, as determined by in vitro competition binding assays. 68Ga labeling was performed in HEPES buffer with microwave heating, and 68Ga-labeled PSMA-11, PSMA-617, HTK01166, and HTK01167 were obtained in 46-69% average decay-corrected radiochemical yield with >99% radiochemical purity and 62.9-152 GBq/µmol average specific activity. PET imaging and biodistribution studies were performed in mice bearing PSMA-expressing LNCap prostate cancer xenografts. All tracers enabled clear visualization of tumors in PET images with excellent tumor-to-background contrast. The uptake values (%ID/g) for tumor and kidneys at 1 h postinjection were 8.91 ± 0.86 and 204 ± 70.6 for 68Ga-PSMA-11, 16.7 ± 2.30 and 29.2 ± 5.14 for 68Ga-PSMA-617, 14.1 ± 4.40 and 147 ± 59.6 for 68Ga-HTK01166, and 7.79 ± 1.65 and 4.30 ± 1.80 for 68Ga-HTK01167. The tumor-to-kidney ratios for 68Ga-labeled PSMA-11, PSMA-617, HTK01166, and HTK01167 were 0.05 ± 0.02, 0.63 ± 0.10, 0.10 ± 0.02, and 1.98 ± 0.63, respectively. Compared with 68Ga-PSMA-617, 68Ga-HTK01166 showed comparable tumor uptake and almost 5-fold higher kidney uptake, whereas 68Ga-HTK01167 exhibited lower tumor and kidney uptake. Compared with 68Ga-PSMA-11, 68Ga-HTK01167 had similar tumor uptake and tumor-to-blood contrast ratio (23.8 ± 6.71 vs 20.4 ± 4.98) but higher tumor-to-background contrast ratios for other background organs especially for kidneys. Our data indicate that substitution of 2-Nal in PSMA-617 with other lipophilic amino acid can modulate PSMA binding affinity and their pharmacokinetics in vivo.

Pharmacokinetics of Daratumumab Following Intravenous Infusion in Relapsed or Refractory Multiple Myeloma After Prior Proteasome Inhibitor and Immunomodulatory Drug Treatment.

Daratumumab is a CD38 monoclonal antibody recently approved for the treatment of multiple myeloma (MM). We report daratumumab pharmacokinetic data from GEN501, a phase I/II dose-escalation (0.005-24 mg/kg) and dose-expansion (8 or 16 mg/kg) study, and SIRIUS, a phase II study (8 or 16 mg/kg), in relapsed or refractory MM. Noncompartmental analysis was conducted to characterize daratumumab pharmacokinetics, and, in both studies, daratumumab exhibited nonlinear pharmacokinetic characteristics. Decreasing daratumumab clearance with increasing dose suggests saturation of target-mediated clearance at higher dose levels, whereas decreasing clearance over time with repeated dosing may be due to tumor burden reductions as CD38-positive cells are eliminated. These and other pharmacokinetic data analyses support the use of the recommended dose regimen of daratumumab (16 mg/kg weekly for 8 weeks, every 2 weeks for 16 weeks, and every 4 weeks thereafter) to rapidly saturate target-mediated clearance during weekly dosing and maintain saturation when dosing every 2 or 4 weeks.

Enhanced intracellular translocation and biodistribution of gold nanoparticles functionalized with a cell-penetrating peptide (VG-21) from vesicular stomatitis virus.

Reduced toxicity and ease of modification make gold nanoparticles (GNPs) suitable for targeted delivery, bioimaging and theranostics by conjugating cell-penetrating peptides (CPPs). This study presents the biodistribution and enhanced intracellular uptake of GNPs functionalized with VG-21, a CPP derived from vesicular stomatitis virus glycoprotein (G). Cell penetrating efficiency of VG-21 was demonstrated using CellPPD web server, conjugated to GNPs and were characterized using, UV-visible and FTIR spectroscopy, transmission electron microscopy, dynamic light scattering and zeta potential. Uptake of VG-21 functionalized GNPs (fGNPs) was tested in eukaryotic cell lines, HEp-2, HeLa, Vero and Cos-7, using flow cytometry, fluorescence and transmission electron microscopy (TEM), and inductively coupled plasmon optical emission spectroscopy (ICP-OES). The effects of nanoparticles on stress and toxicity related genes were studied in HEp-2 cells. Cytokine response to fGNPs was studied in vitro and in vivo. Biodistribution of nanoparticles was studied in BALB/c mice using TEM and ICP-OES. VG-21, GNPs and fGNPs had little to no effect on cell viability. Upon exposure to fGNPs, HEp-2 cells revealed minimal down regulation of stress response genes. fGNPs displayed higher uptake than GNPs in all cell lines with highest internalization by HEp-2, HeLa and Cos-7 cells, in endocytotic vesicles and nuclei. Cytokine ELISA showed that mouse J774 cells exposed to fGNPs produced less IL-6 than did GNP-treated macrophage cells, whereas TNF-α levels were low in both treatment groups. Biodistribution studies in BALB/c mice revealed higher accumulation of fGNPs than GNPs in the liver and spleen. Histopathological analyses showed that fGNP-treated mice accumulated 35 ng/mg tissue and 20 ng/mg tissue gold in spleen and liver respectively, without any adverse effects. Likewise, serum cytokines were low in both GNP- and fGNP-treated mice. Thus, VG-21-conjugated GNPs have enhanced cellular internalization and are suitable for various biomedical applications as nano-conjugates.

GMP production and characterization of leucine zipper-tagged tumor necrosis factor-related apoptosis-inducing ligand (LZ-TRAIL) for phase I clinical trial.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) exhibits potent antitumor activity in a wide range of cancers without deleterious side effects on normal tissues. Several TRAIL derivatives have been developed to improve its pharmacokinetics and therapeutic effects through strategies such as adding a leucine zipper to increase the circulation half-life. To obtain clinical grade LZ-TRAIL for phase I clinical trial, a single batch of 30 L bioreactor culture was performed using the Escherichia coli BL21 (DE3) strain expressing the recombinant LZ-TRAIL. A robust LZ-TRAIL production fermentation process was developed, which could be scaled up from 5L to 50 L, and had a titer of approximately 1.4 g/l. A four-step purification strategy was carried out to obtain a final product with over 95% purity and 45% yield. The final material was filter sterilized, aseptically vialed, and stored at 4°C, and comprehensively characterized using multiple assays (vialed product was sterile, purity was 95%, aggregates were <5%, potency revealed IC50 of 9 nM on MDA-MB-231 cells, and the endotoxin level was <0.25 U/mg). The purity, composition, and functional activities of the molecule were confirmed. in vivo investigations indicated that LZ-TRAIL has better antitumor potency in three Xenograft tumor models compared to TRAIL (95-281). LZ-TRAIL also showed improved pharmacokinetic and safety profiles in cynomolgus monkeys without abnormalities associated with drug exposure. In conclusion, the scalable synthesis of LZ-TRAIL is useful for production of phase I clinical trial material. These preclinical investigations warrant further clinical development of this product for cancer therapy.

P-selectin dependent targeting to inflamed endothelium of recombinant P-selectin glycoprotein ligand-1 immunoglobulin chimera-coated poly[N-(2-hydroxypropyl) methacrylamide]-DNA polyplexes in vivo visualised by intravital microscopy.

BACKGROUND: Developing vectors that target specifically to disease sites after systemic injection is an important goal in gene therapy research. METHODS: We prepared fluorescent DNA polyplexes (< or =150 nm in diameter) comprising plasmid DNA condensed with poly(L-lysine) and coated with a multivalent reactive copolymer based on poly[N-(2-hydroxypropyl)methacrylamide] (pHPMA). These polyplexes were then surface modified with a recombinant P-selectin glycoprotein ligand-1 immunoglobulin chimera (rPSGL-Ig) previously investigated as a selectin antagonist in clinical studies. RESULTS: Five minutes after jugular vein injection of these polyplexes, fluorescence accumulation in inflamed cremasteric venules of C57BL6 mice was more than eight-fold higher than that observed after injection of Fc-blocked control polyplexes. Fluorescence above background was not observed in P-selectin deficient mice, confirming the specificity for P-selectin in this model. CONCLUSIONS: These data provide encouragement for the further development of rPSGL-Ig-coated polyplexes as potential nonviral vectors for targeted gene therapy in inflammatory conditions, such as ischaemia reperfusion injury, unstable atherosclerotic plaques and myocarditis. This approach may also be transferable to the use of other targeting ligands whose cognate partner is specifically upregulated on the vascular endothelium in individual pathological situations.

Plasma bikunin: half-life and tissue uptake.

Bikunin is a chondroitin sulfate-containing plasma protein synthesized in the liver. In vitro, it has been shown to inhibit proteases and to have additional activities, but its biological function is still unclear. Here we have studied the dynamics of plasma bikunin in rats and mice. A half-life of 7 +/- 2 min was obtained from the time course of the decrease of the plasma level of bikunin following hepatectomy. Clearance experiments with intravenously injected radiolabeled bikunin with or without the chondroitin sulfate chain showed that the polysaccharide had little influence on the elimination rate of the protein. The uptake of bikunin by different tissues was studied using bikunin labeled with the residualizing agent 125I-tyramine cellobiose; 60 min after intravenous injection, 49% of the radioactivity was recovered in the kidneys and 6-11% in the liver, bones, skin, intestine and skeletal muscle. The uptake in the liver was analyzed by intravenous injection of radiolabeled bikunin followed by collagenase perfusion and dispersion of the liver cells. These experiments indicated that bikunin is first trapped extracellularly within the liver before being internalized by the cells.

Taurine uptake by human retinal pigment epithelium: implications for the transport of small solutes between the choroid and the outer retina.

PURPOSE: To characterize the Michaelis-Menten kinetics of the taurine transporter (TT) in retinal pigment epithelium (RPE) freshly isolated from human donor eyes. To identify the rate limiting compartment in the pathway of taurine delivery from the choroidal blood supply to the outer retina composed by Bruch's-choroid (BC) and the RPE in the human older age group. METHODS: In human donor samples (4 melanoma-affected eyes, and 14 control eyes; age range, 62-93 years), radiochemical techniques were used to determine the RPE taurine accumulation at various exogenous concentrations. The transport capability of human RPE was obtained from a kinetic analysis of the high-affinity carrier over a substrate concentration of 1 to 60 microM taurine. RESULTS: Uptake of taurine into human RPE at a taurine concentration of 1 microM was independent of donor age (P > 0.05) and averaged at 2.83 +/- 0.27 (SEM) pmol/10 minutes per 6-mm trephine. Taurine transport by human RPE was mediated by a high-affinity carrier of K(m) 50 microM and V(max) of 267 pmol/10 minutes per 5-mm disc. CONCLUSIONS: In human donor RPE, uptake of taurine remained viable in the age range 62 to 93 years. Taurine transport rates in the RPE were lower than across the isolated BC complex, and thus the data suggest that the former compartment houses the rate-limiting step in the delivery of taurine to the outer retina.

Convection-enhanced delivery of tumor necrosis factor-related apoptosis-inducing ligand with systemic administration of temozolomide prolongs survival in an intracranial glioblastoma xenograft model.

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent activator of cell death, preferentially killing neoplastic cells over normal cells, the efficacy of TRAIL for the treatment of glioma might be limited due to cellular resistance and, importantly, poor distribution after systemic administration. TRAIL and temozolomide (TMZ) were recently shown to have a synergistic antitumor effect against U87MG glioma cells in vitro. Convection-enhanced delivery (CED) can effectively distribute TRAIL protein throughout a brain tumor mass. In this study, we evaluated CED of TRAIL, alone and in conjunction with systemic TMZ administration, for antitumor efficacy. CED of TRAIL demonstrated safe and effective distribution in both normal brain and a U87MG intracranial xenograft model. Individually, both CED of TRAIL and systemic TMZ administration prolonged survival in tumor-bearing rats. However, the combination of these two treatments was significantly more effective than either treatment alone. CED of TRAIL in conjunction with systemic TMZ treatment is a promising strategy for the treatment of malignant gliomas.

Tissue distribution, stability, and pharmacokinetics of Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand in human colon carcinoma COLO205 tumor-bearing nude mice.

Apo2L/TRAIL [Apo2 ligand/tumor necrosis factor (TNF)-related apoptosis-inducing ligand], a member of the TNF cytokine superfamily, induces cell death by apoptosis in a number of human cancer cells and is a potential agent for cancer therapy. We have characterized the in vitro stability of Apo2L/TRAIL in human serum and the tissue distribution and metabolism of Apo2L/TRAIL in a xenograft model of human colon carcinoma (COLO205). Apo2L/TRAIL was stable after incubation in human serum, with no significant high molecular weight complexes or degradation products observed. After i.v. administration of 125I-Apo2L/TRAIL to mice, a small percentage of the radiolabeled drug was seen as high molecular weight complex or as low molecular weight degradation products in plasma. However, the most abundant radioactive species corresponded to the intact Apo2L/TRAIL monomer, indicative of the relative stability of this recombinant protein in blood. Distribution of 125I-Apo2L/TRAIL to organs and solid xenograft tumors was limited. Intact 125I-Apo2L/TRAIL was detectable in the solid tumor at all time points and was the only tissue in which radioactivity transiently increased over time. Kidney contained the highest levels of radioactivity. Radioactive signal reached a tissue-to-blood ratio of 18 in the kidney cortex region when 125I-Apo2L/TRAIL was given in the presence of excess unlabeled ligand. In contrast to blood, extensive 125I-Apo2L/TRAIL degradation was observed in the kidney and, to a lesser degree, in the solid tumor and other organs, including liver, spleen, and lung. Our studies demonstrated that Apo2L/TRAIL is stable in the circulation, localizes to human solid xenograft tumors, and is primarily eliminated through the kidney.

Additive effects of TRAIL and paclitaxel on cancer cells: implications for advances in cancer therapy.

In cancer therapy outgrowth of chemoresistant tumor cells is the most important factor that ultimately determines-apart from immediate adverse effects during treatment-the life span and prognosis of cancer patients. Despite many advances in cancer treatment and the integration of supportive medications, including new and better drugs for pain management, antiemesis, infection, and reconstitution of the hematopoietic system, both toxic effects and the development of resistance in response to the treatment remain a major problem. New treatment regimens have to be developed to target cancer more specifically using multiple cellular pathways. This will reduce toxic effects as well as the development of chemoresistance. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is the ligand for death receptors that belong to the TNF death receptor family. TRAIL triggers apoptosis in vitro in various cancer cell types. The antitumor drug, Paclitaxel (PA) was shown to increase the survival of patients with cancer. In in vitro experiments, PA also induces apoptosis in cancer cells. Together, PA and TRAIL lead to tumor regression in in vivo therapy and induce apoptosis through the interaction of TNF family death receptors, caspase activation, and?or cytochrome c release from mitochondria. PA and TRAIL complement each other using two distinct pathways that trigger apoptosis in addition to the anti-microtubule effect of PA. The combination of TRAIL and PA suppresses tumor growth that is otherwise resistant to treatment with either PA or TRAIL alone, by improving proapoptotic effects of the drugs. This observation support the use of the PA and TRAIL in future clinical trials.

Alpha-tocopheryl succinate and TRAIL selectively synergise in induction of apoptosis in human malignant mesothelioma cells.

Malignant mesothelioma (MM) is a fatal type of neoplasia with poor therapeutic prognosis, largely due to resistance to apoptosis. We investigated the apoptotic effect of alpha-tocopheryl succinate (alpha-TOS), a strong proapoptotic agent, in combination with the immunological apoptogen TNF-related apoptosis-inducing ligand (TRAIL) on both MM and nonmalignant mesothelial cells, since MM cells show low susceptibility to the clinically intriguing TRAIL. All MM cell lines tested were sensitive to alpha-TOS-induced apoptosis, and exerted high sensitivity to TRAIL in the presence of subapoptotic doses of the vitamin E analogue. Neither TRAIL or alpha-TOS alone or in combination caused apoptosis in nonmalignant mesothelial cells. Isobologram analysis of the cytotoxicity assays revealed a synergistic interaction between the two agents in MM cells and their antagonistic effect in nonmalignant mesothelial cells. TRAIL-induced apoptosis and its augmentation by alpha-TOS were inhibited by the caspase-8 inhibitor Z-IETD-FMK and the pan-caspase inhibitor Z-VAD-FMK. Activation of caspase-8 was required to induce apoptosis, which was amplified by alpha-TOS via cytochrome c release following Bid cleavage, with ensuing activation of caspase-9. Enhancement of TRAIL-induced apoptosis in MM cells by alpha-TOS was also associated with upregulation of the TRAIL cognate death receptors DR4 and DR5. Our results show that alpha-TOS and TRAIL act in synergism to kill MM cells via mitochondrial pathway, and are nontoxic to nonmalignant mesothelial cells. These findings are indicative of a novel strategy for treatment of thus far fatal MM.

Bikunin plus paclitaxel markedly reduces tumor burden and ascites in mouse model of ovarian cancer.

Our previous studies of intraperitoneal ovarian carcinoma in a mouse model demonstrated that bikunin gene transfection could prevent ascites formation and intraperitoneal disseminated metastasis. Although ascites was almost completely inhibited, tumor burden was variably reduced. Several reports have indicated that bikunin may be involved in tumor survival. In the present study, the effectiveness of exogenous bikunin and the biodistribution characteristics of (125)I-bikunin were initially examined in a mouse model of human ovarian cancer HRA cells. The once-daily i.p. administration of bikunin significantly decreased progressive growth of HRA tumors and ascites formation in a dose-dependent manner. Maximal radioisotope tumor uptake peaked at 7.4% injected dose/g at 3 hr. Bikunin binding specificity was demonstrated by reduced tumor uptake after coinjection of excess nonradioactive bikunin. Bikunin was rapidly excreted renally. The bikunin therapy produced the significant inhibition in expression of the proteolysis (uPA and uPAR) and angiogenesis-related molecules (VEGF and bFGF). The second purpose of our study was to optimize the antimetastatic activity of bikunin in combination with paclitaxel against HRA cells growing orthotopically in mice. The once-daily i.p. administration of bikunin (25 microg/g body weight/day) in combination with paclitaxel (i.p., 100 microg/20 g at days 2 and 5) significantly decreased progressive growth of HRA cells in a synergistic fashion. In conclusion, combination therapy with bikunin plus paclitaxel may be an effective way to markedly reduce i.p. tumor growth and ascites in ovarian carcinoma possibly through suppression of uPA, uPAR, VEGF and bFGF expression.

The transcriptosomal response of human A549 lung cells to a hydrogen peroxide-generating system: relationship to DNA damage, cell cycle arrest, and caspase activation.

Intracellular oxidative stress is a dynamic situation characterized by the accumulation of reactive oxygen metabolites, such as hydrogen peroxide. This is traditionally associated with both macromolecular damage and adaptive changes in gene expression, aimed at preventing cellular demise. However, the overall extent of such genetic changes is not well characterized. Here we present a comprehensive analysis of altered mRNA profiles in human A549 type II lung epithelial cells in response to hydrogen peroxide, at concentrations failing to induce necrotic toxicity. The results of an Affymetrix-based screen of the steady-state levels of mRNAs for several thousand genes revealed a complex pattern of transcriptional and/or posttranscriptional response to oxidative stress, which can be functionally related to both the oxidation and repair of damaged DNA, the induction and permanency of cell cycle arrest, and caspase-3 activation. Many of the genetic events can be related to activation of the p53/p21 pathway, but many other novel inductions and suppressions were detected, revealing the intricacy of the response. The data also disclosed a potential interaction between hydrogen peroxide treatment and increased sensitivity to cell killing by TRAIL, which could be functionally confirmed at the level of induction of caspase-3 activity.

Therapeutic efficacy of once-daily oral administration of a Kunitz-type protease inhibitor, bikunin, in a mouse model and in human cancer.

BACKGROUND: Bikunin, a Kunitz-type protease inhibitor, specifically inhibits tumor invasion and metastasis. METHODS: The authors initially evaluated the therapeutic efficacy of once-daily oral administration of different doses of bikunin against human ovarian carcinoma HRA cells growing in the peritonea of nude mice. For the in vivo studies, female 7-week-old nude mice were randomized to 1 of 4 groups: bikunin-treated groups (n = 9 in each group) received 3, 10, or 30 microg/g body weight per day bikunin for 7 days via gastrointestinal gavage, and a control group (n = 9) received the vehicle solution (phosphate-buffered saline) via gastrointestinal gavage. On Day 9, the abdominal cavity was examined by two observers who were blinded to treatment. RESULTS: After oral administration, intact bikunin was detectable in mouse serum specimens at 3 and 6 hours. This was followed by a decline at 12 hours. The mice given bikunin at the highest dose level had a 40% decrease in tumor load. The highest uptake in the tumor was obtained with [125I]bikunin 12 hours postadministration. No effect on either food intake or body weight was observed in the treated versus sham groups. The current study was the first to report the potent activity of once-daily oral administration of bikunin against ovarian carcinoma. Next, the authors performed a Phase I trial to determine the maximum-tolerated dose (MTD) and safety of a once-daily oral administration schedule. The indication was locally advanced uterine cervical carcinoma after definitive treatment. An escalating dose (3, 10, and 30 mg/kg per day) of bikunin was administered orally to nine patients for 7 days. There were no dose-limiting toxicities and the MTD of the bikunin schedule was not defined. The authors also obtained preliminary data on its effect on urokinase-type plasminogen activator expression at the highest dose level. CONCLUSIONS: Once-daily oral administration of bikunin was found to be safe in humans and exhibited signs of biologic activity.

Efficacy of targeted FasL in nasopharyngeal carcinoma.

We have successfully achieved selective gene expression in human nasopharyngeal carcinoma (NPC) by exploiting the presence of the Epstein-Barr virus (EBV), utilizing a transcriptional targeting strategy (J. H. Li et al., 2002, Cancer Res. 62: 171). Building on this platform, we have generated a novel DeltaE1 adenoviral vector mediating the expression of a mutant noncleavable form of the FasL gene (HUGO-approved symbol TNFSF6) (ad5oriP.ncFasL). We observe that this therapy induces significant cytotoxicity in the EBV-positive NPC cell line C666-1, mediated by the induction of caspase-dependent apoptosis. The addition of ionizing radiation therapy (RT) causes additional cytotoxicity. Ex vivo infection of C666-1 cells with adv.oriP.ncFasL completely prevents tumor formation in SCID mice followed for up to 100 days. The combination of intratumoral adv.oriP.ncFasL with RT causes regression of established nasopharyngeal xenograft tumors for 2 weeks' duration. Systemic delivery of this targeted strategy achieves 50-fold higher gene expression in nasopharyngeal tumors than in normal organs. Intravenously injected adv.oriP.ncFasL results in mild perturbation of liver function that returns to normal 2 weeks after initial therapy. These results demonstrate the efficacy of our EBV-specific targeting strategy, which allows the potentially safe and effective utilization of a highly potent membrane-based apoptotic gene.