Antitumor Efficacy of Intravesical BCG, Gemcitabine, Interferon-α and Interleukin-2 as Mono- or Combination-Therapy for Bladder Cancer in an Orthotopic Tumor Model

Objective:

To reduce adverse effects and improve efficacy of intravesical BCG for bladder cancer, alternative treatment options were investigated in an orthotopic rat tumor model.

Methods:

Superficial bladder cancer was established in syngeneic female rat bladders by instillation of AY-27 cells. Animals were randomly assigned to treatment groups including dose escalation of intravesical BCG with or without interferon-α (IFN-α) or interleukin-2 (IL-2); or graded doses of gemcitabine alone; or BCG plus gemcitabine. Treatments were given twice weekly for 3 weeks. Rats in control groups received saline instillations. Treatment response was monitored by animals’ well-being, survival days, tumor growth inhibition, and histological examination at necropsy.

Results:

Rats receiving monotherapy with intravesical BCG, gemcitabine, or IFN-α, attained significantly better survival and tumor reduction compared with control (P = 0.002; 0.001; 0.002, respectively, Log-rank Test). A dose-dependent treatment response was observed in animals with established bladder tumor receiving escalated BCG instillations. Only high-dose BCG significantly improved animal survival. Although high-dose BCG plus gemcitabine or IFN-α did not increase benefit over monotherapies, low-dose BCG plus IL-2 did show improved efficacy (P = 0.01).

Conclusion:

Intravesical monotherapies with gemcitabine and IFN-α were as effective as BCG for treatment of early non-muscle-invasive urothelial bladder cancer in this immune competent rat model. Combining these agents with high-dose BCG did not further increase efficacy. However, combining low-dose BCG with IL-2 enhanced BCG effectiveness.

A novel oncogenic role for the miRNA-506-514 cluster in initiating melanocyte transformation and promoting melanoma growth

Malignant melanoma is the most aggressive form of skin cancer and its incidence has doubled in the last two decades. It represents only 4% of skin cancer cases per year, but causes as many as 74% of skin cancer deaths. Early detection of malignant melanoma is associated with survival rates of up to 90%, but later detection (stage III to stage IV) is associated with survival rates of only 10%. Dysregulation of microRNA (miRNA) expression has been linked to tumor development and progression by functioning either as a tumor suppressor, an oncogene or a metastasis regulator in multiple cancer types. To understand the role of miRNA in the pathogenesis of malignant melanoma and identify biomarkers of metastasis, miRNA expression profiles in skin punches from 33 metastatic melanoma patients and 14 normal healthy donors were compared. We identified a cluster of 14 miRNAs on the X chromosome, termed the miR-506-514 cluster, which was consistently overexpressed in nearly all melanomas tested (30-60 fold, P<0.001), regardless of mutations in N-ras or B-raf. Inhibition of the expression of this cluster as a whole, or one of its sub-clusters (Sub-cluster A) consisting of six mature miRNAs, led to significant inhibition of cell growth, induction of apoptosis, decreased invasiveness and decreased colony formation in soft agar across multiple melanoma cell lines. Sub-cluster A of the miR-506-514 cluster was critical for maintaining the cancer phenotype, but the overexpression of the full cluster was necessary for melanocyte transformation. Our results provide new insights into the functional role of this miRNA cluster in melanoma, and suggest new approaches to treat or diagnose this disease.

Hepatitis B virus X protein downregulates expression of the miR-16 family in malignant hepatocytes in vitro

BACKGROUND

Hepatitis B virus X protein (HBx) is involved in the initiation and progression of hepatocellular carcinoma (HCC) by regulating the host protein-coding genes. In this study, we showed that HBx altered the expression of microRNAs (miRNAs) to promote proliferation and transformation in malignant hepatocytes in vitro.

METHODS

miRNA microarray and quantitative reverse-transcription polymerase chain reactions (qRT-PCRs) were performed to identify miRNAs that were differentially regulated by HBx in HCC cells. Protein, mRNA, and miRNA expression analyses; cell cycle and apoptosis analyses; loss/gain-of-function analysis; and luciferase reporter assays were performed to delineate the consequences of miR-16 family repression in HepG2 cells.

RESULTS

Hepatitis B virus X protein induced widespread deregulation of miRNAs in HepG2 cells, and the downregulation of the miR-16 family was reproducible in HepG2, SK-HEP-1, and Huh7 cells. CCND1, a target of the miR-16 family, was derepressed by HBx in HepG2 cells. c-Myc mediated the HBx-induced repression of miR-15a/16 in HepG2 cells. Ectopically expressed miR-15a/16 suppressed the proliferation, clonogenicity, and anchorage-independent growth of HBx-expressing HepG2 cells by arresting them in the G1 phase and inducing apoptosis, whereas reduced expression of miR-16 accelerated the growth and cell-cycle progression of HepG2 cells.

CONCLUSIONS

Hepatitis B virus X protein altered the in vitro expression of miRNAs in host malignant hepatocytes, particularly downregulating the miR-16 family. Repression of miR-15a/16 is c-Myc mediated and is required for the HBx-induced transformation of HepG2 cells in vitro. Therefore, miR-16 family may serve as a therapeutic target for hepatitis B virus (HBV)-associated HCC.

Abstract P6-15-08: KGFR Tyrosine Kinase Inhibitors for the Treatment of Breast Cancer

Background: Keratinocyte growth factor (KGF) produces a rapid increase in the proliferation and motility of estrogen receptor (ER)-positive breast cancer cells (Zang, XP and Pento, JT, Clin. & Exptl. Metastasis 18: 573-80, 2001). It has been demonstrated that the KGF receptor (KGFR) is up-regulated in breast cancer; thus, KGF/KGFR signaling appears to be an early event in breast cancer progression (Zang, XP, Lerner, ML, Bahr, SJ, Brackett, DJ and Pento, JT, Cancer Genomics & Proteomics, 3: 369-72, 2006). Molecular modeling was used to create group of KGFR selective tyrosine kinase inhibitors (TKI) (Pento, JT and Li, PK, Drugs of the Future, 32: 965-72, 2007). The present study examined the effect of a group of these compounds on KGF-mediated proliferation and Erk signaling in MCF-7 breast cancer cells. In addition, the oncolytic potential of compound L-27, a potent KGFR TKI, was examined in an orthotopic xenograft model of human breast cancer.

Methods: A group of high affinity KGFR TKI were tested for their ability to inhibit KGF-mediated proliferation and Erk phosphorylation in MCF-7 cells using MTS and ELISA assays. In addition, immuno-cytochemistry was used to examine the influence of the 5 most potent inhibitor compounds on the density of cell membrane KGFR. The effects of a KGFR TKI on breast cancer growth and progression in vivo was examined using an orthotopic xenograft model, with clones of MCF-7 cells which were transfected with a KGF-producing plasmid to enhance cell growth and metastasis and a GFP reporter to quantify tumor growth and metastasis. PET imaging was also used to identify metastatic development.

Results: From the initial group of 53 compounds, 5 compounds were observed to produce greater than 50% inhibition of KGF-mediated cancer cell proliferation, reduce Erk phosphorylation and the density of the KGFR on the membrane surface of the cancer cells. Compound L-27, one of the most potent KGFR inhibitors, reduced the growth of MCF-7 tumors and metastatic development in the xenograft model in a dose-related fashion at doses of 4, 10 and 25 mg/kg. Animal weights in the treatment groups remained the same as the control group; indicating a lack of toxicity at the doses employed.

Discussion: The novel compounds tested in this project reduce or abolish KGF-mediated proliferation, Erk signaling and KGFR membrane density in vitro. In addition, compound L-27, a potent KGFR inhibitor in vitro, was found to reduce the progression of MCF-7 tumor xenografts in vivo. In conclusion, the KGFR TKI represent a novel class of anticancer agents for the prevention of metastatic progression and may provide a new therapeutic approach for the treatment of breast and other cancers. Acknowledgement: This work was supported by the grants from DoD (DAMD17-01-1-0591) and the NCI (CA-89740) and (CA-125493).

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-15-08.

Development of rapid immunoassays for the detection of ractopamine in swine urine

The monoclonal antibodies (mAbs) against ractopamine (Rac) were prepared and their properties identified by indirect competitive enzyme-linked immunoabsorbant assay (ELISA). The IC(50) of mAbs was 2.7 ng ml(-1) towards Rac or 9.3 ng ml(-1) towards Rac-glucuronides and no cross-reactivity (CR) towards other competitors except dobutamine (CR: 3.76%). Based on the mAbs, the Rac-kit (kit) and Rac-strip (strip) were developed to detect Rac residues in swine urine. The strip and kit assay could be performed within 5-10 min and 2 h, respectively, allowing the analysis of urine samples without the need for sample clean-up. The detection limits were 1 ng ml(-1) for kit and 3 ng ml(-1) with the unaided eye, and 0.2 ng ml(-1) with the Strip Reader for strip. The correlation coefficients (R(2)) were 0.988 for kit in the range 0-128.0 ng ml(-1), and 0.987 for strip in the range 0-10.8 ng ml(-1). Comparing the gas chromatography-mass spectrometry (GC-MS) with the kit or strip in swine urine spiked with Rac standards, the differences ranged from 1.4% to 4.5% for kit and 1.0% to 4.7% for strip. However, the differences were greater than 54% for the kit and 55% for the strip test for the analysis of urine from swine treated with Rac. The results obtained from GC-MS using hydrolysed urine samples were generally in good agreement with those obtained from strip or kit using non-hydrolysed urine samples.

Acute effects of sublingual buprenorphine on brain responses to heroin-related cues in early-abstinent heroin addicts: an uncontrolled trial

Replacement therapy with buprenorphine is clinically effective in reducing withdrawal and craving for heroin during detoxification but not in decreasing the probability of relapse after detoxification. This study examined the acute effects of buprenorphine on brain responses to heroin-related cues to reveal the neurobiological and therapeutic mechanisms of addiction and relapse. Fifteen heroin addicts at a very early period of abstinence, were studied in two separate periods 10-15 min apart: an early period (5-45 min) and a later period (60-105 min) after sublingual buprenorphine, roughly covering the onset and peak of buprenorphine plasma level. During both periods, fMRI scanning with heroin-related visual stimuli were performed followed by questionnaires. Under effect of buprenorphine, brain responses to heroin-related cues showed decrease in amygdala, hippocampus, ventral tegmental area (VTA) and thalamus but no changes in ventral striatum and orbital-prefrontal-parietal cortices. As an uncontrolled trial, these preliminary results suggest that buprenorphine has specific brain targets in reducing withdrawal and craving during early abstinence, and that ventral striatum and orbital-prefrontal-parietal cortices may be the key targets in developing therapy for drug addiction and relapse.

The fabrication of carbon nanotube field-effect transistors with semiconductors as the source and drain contact materials

Sb(2)Te(3) and Bi(2)Te(2)Se semiconductor materials were used as the source and drain contact materials in the fabrication of carbon nanotube field-effect transistors (CNTFETs). Ultra-purified single-walled carbon nanotubes (SWCNTs) were ultrasonically dispersed in N-methyl pyrrolidone solvent. Dielectrophoresis was used to deposit and align SWCNTs for fabrication of CNTFETs. The Sb(2)Te(3)- and Bi(2)Te(2)Se-based CNTFETs demonstrate p-type metal-oxide-silicon-like I-V curves with high on/off drain-source current ratio at large drain-source voltages and good saturation of drain-source current with increasing drain-source voltage. The fabrication process developed is novel and has general meaning, and could be used for the fabrication of SWCNT-based integrated devices and systems with semiconductor contact materials.

Response of bladder carcinoma cells to TRAIL and antisense oligonucleotide, Bcl-2 or clusterin treatments

PURPOSE

Bladder transitional cell carcinoma is the second most common urological malignancy, of which 80% are superficial disease limited to the bladder. Superficial bladder transitional cell carcinoma has a high propensity for recurrence and progression after initial resection, necessitating adjuvant intravesical therapy. TRAIL (tumor necrosis factor-related apoptosis inducing ligand) can selectively induce apoptosis in most tumor cells while sparing normal cells. TRAIL drives not only the death receptor pathway, but also the mitochondrial pathway through Bid. Due to the anti-apoptotic functions of Bcl-2 and clusterin on the mitochondrial apoptotic pathway the effects of down-regulating these proteins were examined in partially TRAIL resistant bladder transitional cell carcinoma cell lines.

MATERIALS AND METHODS

Antisense oligonucleotides targeting Bcl-2 and clusterin were used alone or combined with TRAIL and cytotoxicity was examined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide) proliferation assay. Apoptotic pathway signals were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/Western blotting after the various combination treatments. All statistical tests were 2 sided.

RESULTS

Although no direct correlation between TRAIL sensitivity and the relative expression levels of Bcl-2 and clusterin was found in the bladder transitional cell carcinoma cell lines examined, antisense oligonucleotide mediated the down-regulation of Bcl-2 and clusterin, increasing the sensitivity of the partially resistant cells to TRAIL. This was mediated through increased apoptotic signaling of the mitochondrial pathway, as evident by the increased activation of caspase-9 and 3, and cleaved DFF45. There was no benefit of combined antisense oligonucleotide therapy.

CONCLUSIONS

This study provides proof of principle that TRAIL combined with antisense oligonucleotide-Bcl-2 may have potential as a novel future treatment strategy for bladder transitional cell carcinoma.