Biomedical subjects

Frida Ponthan

Publications and source records attributed to Frida Ponthan.

10 recordsLinked to original sources

PubMed2006

The antimicrobial peptide, lactoferricin B, is cytotoxic to neuroblastoma cells in vitro and inhibits xenograft growth in vivo.

Antimicrobial peptides have been shown to exert cytotoxic activity towards cancer cells through their ability to interact with negatively charged cell membranes. In this study the cytotoxic effect of the antimicrobial peptide, LfcinB was tested in a panel of human neuroblastoma cell lines. LfcinB displayed a selective cytotoxic activity against both MYCN-amplified and non-MYCN-amplified cell lines. Non-transformed fibroblasts were not substantially affected by LfcinB. Treatment of neuroblastoma cells with LfcinB induced rapid destabilization of the cytoplasmic membrane and formation of membrane blebs. Depolarization of the mitochondria membranes and irreversible changes in the mitochondria morphology was also evident. Immuno- and fluorescence-labeled LfcinB revealed that the peptide co-localized with mitochondria. Furthermore, treatment of neuroblastoma cells with LfcinB induced cleavage of caspase-6, -7 and -9 followed by cell death. However, neither addition of the pan-caspase inhibitor, zVAD-fmk, or specific caspase inhibitors could reverse the cytotoxic effect induced by LfcinB. Treatment of established SH-SY-5Y neuroblastoma xenografts with repeated injections of LfcinB resulted in significant tumor growth inhibition. These results revealed a selective destabilizing effect of LfcinB on two important targets in the neuroblastoma cells, the cytoplasmic- and the mitochondria membrane.

Animals↗

PubMed2006

Neuroblastoma cell death in response to docosahexaenoic acid: sensitization to chemotherapy and arsenic-induced oxidative stress.

Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid vital for the developing nervous system and significantly decreased in neuroblastoma cells compared to nontransformed nervous tissue. We investigated whether supplementation of DHA affects the susceptibility of neuroblastoma cells to oxidative stress generated endogenously and in response to cytotoxic therapy. DHA, but not the monounsaturated oleic acid (OA), induced dose- and time-dependent neuroblastoma cell death. DHA supplementation was associated with depolarization of the mitochondrial membrane potential, production of reactive oxygen species (ROS) and accumulation of DNA in sub-G1 phase of the cell cycle. The antioxidant, vitamin E, inhibited mitochondrial depolarization and subsequent cell death induced by DHA, whereas, the mitochondrial pore inhibitor, cyclosporin A, partly inhibited DHA-induced neuroblastoma cell death. Depletion of glutathione by L-buthionine-sulfoximine significantly enhanced the cytotoxic effects of DHA. Nontransformed fibroblasts were not substantially affected by DHA. DHA, but not OA, significantly enhanced the cytotoxicity of cisplatin, doxorubicin and irinotecan both in chemosensitive and in multidrug-resistant neuroblastoma cells. DHA potently sensitized neuroblastoma cells to a clinically relevant concentration (1 microM) of arsenic trioxide (As2O3) and enhanced the effect of the nonsteroidal antiinflammatory drug (NSAID), diclofenac. These findings provide experimental evidence that the omega-3 fatty acid, DHA, is cytotoxic to drug-resistant neuroblastoma. The potent action of DHA with arsenic trioxide, NSAID and chemotherapeutic agents suggests clinical testing of this therapeutic concept in children with neuroblastoma.

Antioxidants↗

PubMed2005

Proton magnetic resonance spectroscopy in neuroblastoma: current status, prospects and limitations.

Non-invasive biological information about residual neuroblastoma tumour tissue could allow treatment monitoring without the need for repeated biopsies. Magnetic resonance spectroscopy (MRS) can be performed with standard MR-scanners, providing specific biochemical information from selected tumour regions. By proton 1H-MRS, lipids, certain amino acids and lactate can be detected and their relative concentrations estimated in vivo. Using experimental models of neuroblastoma, we have described the potential of 1H-MRS for the prediction of tumour tissue viability and treatment response. Whereas viable neuroblastoma tissue is dominated by the choline 1H-MRS resonance, cell death as a consequence of spontaneous necrosis or successful treatment with chemotherapy, angiogenesis inhibitors, or NSAIDs is associated with decreased choline content. Therapy-induced neuroblastoma cell death is also associated with enhanced 1H-MRS resonances from mobile lipids and polyunsaturated fatty acids. The mobile lipid/choline ratio correlates significantly with cell death and based on the dynamics of this ratio tumour regression or continued growth (drug resistance) after chemotherapy can be predicted in vivo. The implications of these findings are discussed with focus on the potentials and limitations of introducing 1H-MRS for clinical assessment of treatment response in children with neuroblastoma. Biochemical monitoring of neuroblastoma with 1H-MRS could enable tailoring of individual therapy as well as provide early pharmacodynamic evaluation of novel therapeutic modalities.

Humans↗

PubMed2005

NSAIDs in neuroblastoma therapy.

Cyclooxygenases (COX) catalyse the conversion of arachidonic acid to prostaglandins. COX-2 is upregulated in several adult epithelial cancers. In neuroblastoma it has been shown that the majority of primary tumours and cell lines express high levels of COX-2, whereas normal adrenal medullas from children do not express COX-2. Treatment of neuroblastoma cells with nonsteroidal anti-inflammatory drugs (NSAIDs), inhibitors of COX, induces caspase-dependent apoptosis via the intrinsic mitochondrial pathway. Established neuroblastoma xenografts in nude rats treated with the dual COX-1/COX-2 inhibitor, diclofenac, or the COX-2 specific inhibitor, celecoxib significantly inhibits neuroblastoma growth in vivo. In vitro, arachidonic acid and diclofenac synergistically induces neuroblastoma cell death. This effect is further pronounced when lipoxygenases is inhibited simultaneously. Proton MR-spectroscopy (1H MRS) of neuroblastoma cells treated with COX-inhibitors demonstrates accumulation of polyunsaturated fatty acids and depletion of choline compounds. Thus, 1H MRS, which can be performed with clinical MR-scanners, is likely to provide pharmacodynamic markers of neuroblastoma response to COX-inhibition. Taken together, these data suggest the use of NSAIDs as a novel adjuvant therapy for children with neuroblastoma.

Animals↗

PubMed2004

Cyclooxygenase-2 is expressed in neuroblastoma, and nonsteroidal anti-inflammatory drugs induce apoptosis and inhibit tumor growth in vivo.

Neuroblastoma is the single most common and deadly tumor of childhood and is often associated with therapy resistance. Cyclooxygenases (COXs) catalyze the conversion of arachidonic acid to prostaglandins. COX-2 is up-regulated in several adult epithelial cancers and is linked to proliferation and resistance to apoptosis. We detected COX-2 expression in neuroblastoma primary tumors and cell lines but not in normal adrenal medullas from children. Treatment of neuroblastoma cells with nonsteroidal anti-inflammatory drugs, inhibitors of COX, induced caspase-dependent apoptosis via the intrinsic mitochondrial pathway. Treatment of established neuroblastoma xenografts in nude rats with the dual COX-1/COX-2 inhibitor diclofenac or the COX-2-specific inhibitor celecoxib significantly inhibited tumor growth in vivo (P < 0.001). In vitro, arachidonic acid and diclofenac synergistically induced neuroblastoma cell death. This effect was further pronounced when lipooxygenases were simultaneously inhibited. Proton magnetic resonance spectroscopy ((1)H MRS) of neuroblastoma cells treated with COX inhibitors demonstrated accumulation of polyunsaturated fatty acids and depletion of choline compounds. Thus, (1)H MRS, which can be performed with clinical magnetic resonance scanners, is likely to provide pharmacodynamic markers of neuroblastoma response to COX inhibition. Taken together, these data suggest the use of nonsteroidal anti-inflammatory drugs as a novel adjuvant therapy for children with neuroblastoma.

Adrenal Gland Neoplasms↗

PubMed2004

Synergistic induction of apoptosis in neuroblastoma cells using a combination of cytostatic drugs with interferon-gamma and TRAIL.

The majority of high-risk neuroblastomas lack the expression of caspase-8 due to gene silencing which suggest a mechanism for the selection of tumour cells that are refractory to multiple cytotoxic drugs including tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Inhibitors of DNA methyltransferases and IFN-gamma induce expression of caspase-8, and sensitise some neuroblastoma cells to TRAIL-mediated apoptosis. Here we demonstrate that a combination of cytostatic drugs with IFN-gamma and TRAIL synergistically induces neuroblastoma cell death, which may have implications for future therapy of children with neuroblastoma. Treatment of neuroblastoma cells with IFN-gamma induced caspase-8 expression in all cell lines investigated. In five of the neuroblastoma cell lines (SHEP-1, SK-N-AS, SK-N-FI, SH-SY-5Y and Kelly), IFN-gamma promoted TRAIL-mediated cleavage of caspase-8, initiating a caspase cascade involving caspase-7 and PARP followed by apoptosis. IFN-gamma-mediated facilitation of apoptosis was inhibited by the pan-caspase inhibitor zVAD-fmk and the caspase-8 specific inhibitor zIEDT-fmk, indicating an important role of caspase-8 in mediating sensitation by IFN-gamma in neuroblastoma cells. In three of the cell lines [SK-N-BE(2), SK-N-DZ and IMR-32] caspase-8 expression was induced by IFN-gamma, but the cells were still resistant to TRAIL-mediated apoptosis. The pattern of basal TRAIL receptor expression, decoy receptors, FLIP and FADD could not be correlated with resistance or sensitivity to TRAIL-induced apoptosis. Importantly, treatment of neuroblastoma cell lines with cytostatic drugs increased apoptosis in the TRAIL-sensitive cell lines whereas the resistant cell lines were susceptible to TRAIL-mediated apoptosis in the presence of the anticancer drugs. The mechanism of the increased susceptibility to apoptosis might results from drug-mediated up-regulation of the death receptors DR4 and DR5.

Antineoplastic Agents↗

PubMed2003

The synthetic retinoid RO 13-6307 induces neuroblastoma differentiation in vitro and inhibits neuroblastoma tumour growth in vivo.

Retinoids modulate cell proliferation, differentiation and apoptosis in a variety of tumour cells including leukaemia and neuroblastoma, a childhood tumour of the sympathetic nervous system. 13-cis retinoic acid is in clinical use against minimal residual disease in neuroblastoma, where the effect seems to depend on dose, scheduling and tumour mass. Novel retinoids are searched for, to improve potency and lower toxicity. We investigated the effect of the synthetic retinoid Ro 13-6307 on neuroblastoma growth in vitro on SK-N-BE(2) and SH-SY5Y cells. Furthermore, effects on tumour growth and the toxicity profile were investigated in a rat xenograft model. Effects of Ro 13-6307 were compared to 13-cis RA (retinoic acid) in vitro and in vivo. Neuroblastoma cells treated with 1 microM Ro 13-6307 exhibited neuronal differentiation, decreased proliferation and accumulation of cells in G1 phase in at least the same magnitude as 5 microM 13-cis RA. No apoptosis was detected in vitro. Treatment of nude rats with neuroblastoma using Ro 13-6307, 0.12 mg p.o. daily, decreased neuroblastoma growth in vivo, in terms of tumour volume during treatment and tumour weight at sacrifice (p < 0.05). In contrast, Ro 13-6307, 0.08 mg p.o. daily, resulted in no significant reduction in tumour growth. All rats treated with Ro 13-6307 gained less weight than control rats, but they exhibited no other signs of toxicity. The toxicity profile of Ro 13-6307 was similar to what we found with 13-cis RA. Our preclinical results suggest that Ro 13-6307 may be a candidate retinoid for clinical oral therapy of neuroblastoma in children.

Animals↗

PubMed2003

Quantitative analysis of tyrosine hydroxylase mRNA for sensitive detection of neuroblastoma cells in blood and bone marrow.

BACKGROUND: Sensitive monitoring of minimal residual disease may improve the treatment of neuroblastoma in children. To detect and monitor neuroblastoma cells in blood and bone marrow, we developed a quantitative method for the analysis of tyrosine hydroxylase mRNA. METHODS: We used real-time reverse transcription-PCR. The calibrator was constructed from a segment of tyrosine hydroxylase mRNA that included the target. Blood and bone marrow samples from 24 children with neuroblastoma and 1 child with ganglioneuroma were analyzed. Controls were blood samples from the cords of 40 babies, from 58 children 6 months to 15 years of age, and from 34 healthy adults, as well as from 12 children with other diseases. RESULTS: The detection limit was approximately 70 transcripts/mL. All 144 blood controls were below this limit. At diagnosis, blood tyrosine hydroxylase mRNA was higher in children with widespread disease (stage 4/4S; n = 6; range, 203-46,000 transcripts/mL) than in patients with localized disease (stages 1-3; n = 6; </=83 transcripts/mL; P = 0.002). Bone marrow from all five children with localized disease had concentrations <72 transcripts/mL, whereas five of six stage 4 patients had increased concentrations (6,000-8,000,000 transcripts/mL; P <0.05). In nine children in whom tyrosine hydroxylase mRNA was measured repeatedly, the results corresponded to the clinical course. CONCLUSION: Quantitative analysis of tyrosine hydroxylase mRNA in blood and bone marrow is reliable and easy to perform and may be used for upfront staging, prognostic assessment, and treatment monitoring of neuroblastoma.

Adolescent↗

PubMed2003

Apoptosis and tumor remission in liver tumor xenografts by 4-phenylbutyrate.

4-phenylbutyrate (triButyrate trade mark, PB) a derivative of the short-chain fatty acid, butyrate, possesses anti-tumor activity in vitro in different tumor cell lines. Unlike most cytostatic compounds, PB possesses low toxicity. In order to evaluate possible clinical use of PB in cancer therapy, hepatocarcinoma (Hep3B) and hepatoblastoma (HepT1) cell lines, as well as xenografts derived from those in nude rats, were treated with PB in different dose (1-100 mM) and time regimens. Treatment with 10 mM of PB for 24 h (or 5 mM for 48 h) was shown to significantly inhibit Hep3B cell growth in vitro. The HepT1 cell line was more sensitive to PB treatment: already 1 mM of PB for 24 h significantly inhibited the growth of the cells. PB also resulted in regression of xenografts derived from these cell lines in vivo, when administrated by mini-pump with an intratumor catheter, yielding 20 micro mol of PB per cm3 of tumor volume per day. TUNEL assay and caspase-3 activity measurements suggested apoptosis to be the cell death mechanism in both cell lines and xenografts. Increased histones H3 and H4 acetylation was shown in both cells and xenografts, and the inhibition of histone deacetylase is proposed as the main trigger for the anti-tumor action of PB. Concomitant induction of p21Waf1/Cip1 expression was detected by RNase protection assay and Western blotting. Reduction in expression of alpha-fetoprotein was found both in Hep3B cells and xenografts, suggesting also a differentiation effect by PB.

Acetylation↗

PubMedDate not supplied

Evaluation of anti-tumour effects of oral fenretinide (4-HPR) in rats with human neuroblastoma xenografts.

Neuroblastoma, the most common extracranial solid tumour in children, may undergo spontaneous differentiation or regression, but the majority of metastatic neuroblastomas have poor prognosis despite intensive treatment. Retinoic acid and its analogues regulate growth and differentiation of neuroblastoma cells in vitro, and 13-cis retinoic acid has shown activity against human neuroblastomas in vivo. Fenretinide [N-(4-hydroxyphenyl)retinamide] has been identified as a synthetic retinoid able to induce apoptosis of numerous malignant cell lines in vitro, including neuroblastoma. Furthermore, in animal models, fenretinide has shown chemopreventive and therapeutic efficacy against several malignancies without any obvious signs of toxicity. To investigate the anti-neuroblastoma tumour growth effects of oral fenretinide in vivo we used a human neuroblastoma xenograft model. Nude rats with established neuroblastoma xenograft tumours were treated orally with fenretinide for 10 days. Five different doses of fenretinide were used ranging from 2.5 to 75 mg/rat/day (10-300 mg/kg). Tumour volumes and toxic side effects were monitored during treatment and tumour weights were recorded at autopsy. In this study we found no significant anti-tumour growth effects of fenretinide in vivo, when used as oral treatment of rats with established neuroblastoma xenograft tumours. Furthermore, there were no intra tumoural differences in treated compared to untreated tumours. However, because of the promising results of fenretinide on neuroblastoma growth in vitro, further in vivo studies are warranted using other modalities of drug administration.

Administration, Oral↗