[Show abstract][Hide abstract] ABSTRACT: Background:
The identification and management of hemolyzed samples are crucial issues in the development of new blood-based biomarkers.
Using experiments of controlled hemolysis and lipemia and two plasma series from cancer patients, we developed and validated a lipemia-independent hemolysis score (HS). HS resulted strictly associated with the amount of lysed erythrocytes and with serum index measurement (reference method), highly reproducible, and able to identify as hemolyzed plasma/serum samples containing ≥6.1 mg/dl of free hemoglobin.
We developed a simple, robust, sensitive, cost-effective, spectrophotometrically-based system to identify hemolyzed plasma/serum specimens. The procedure requires only 2 μl of sample, thus representing a useful tool for research studies and an essential pre-analytical quality control for an optimal biobanking of liquid biopsies.
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs have been found to be deregulated in several diseases and, due to their high stability in body fluids, represent promising non-invasively detectable biomarkers. However, numerous technical variables can affect accurate measurement of circulating miRNAs. Using a microarray-based method we assessed the: i) adequate intra- and interarray reproducibility of miRNA profiling; ii) feasibility of using archival plasma samples stored for an extended period of time and available in limited amounts; iii) good correlation between different batches and iv) time-dependent increase of background signals close to the chip expiration date.
Full-text · Article · Mar 2013 · Analytical Biochemistry
[Show abstract][Hide abstract] ABSTRACT: This Correspondence relates to the desciption of an optimized strategy for the detection of circulating cancer-related microRNA as discussed by Kim et al (J Mol Diagn 2012, 14:71-80).
Full-text · Article · Jan 2013 · The Journal of molecular diagnostics: JMD
[Show abstract][Hide abstract] ABSTRACT: Fenretinide (4-HPR) is a synthetic retinoid that exhibits potent antitumor and chemopreventive activities against different malignancies, including ovarian tumors. We previously showed that in ovarian cancer cells, 4-HPR induces apoptosis through a signaling cascade starting from reactive oxygen species (ROS) generation and involving endoplasmic reticulum (ER) stress response, Jun N-terminal Kinase (JNK) activation, and induction of the proapoptotic PLAcental Bone morphogenetic protein (PLAB). Since recent studies have shown that the oncogene ALL1-fused from chromosome 1q (AF1q), a retinoic acid target gene, is implicated in apoptosis induction by several therapeutic agents, we investigated its possible involvement in the apoptosis induced by 4-HPR in ovarian cancer cells.
[Show abstract][Hide abstract] ABSTRACT: The major limitation to successful chemotherapy of neuroblastoma (NB) is the toxicity and the poor bioavailability of traditional drugs.
We synthesised an amphiphilic dextrin derivative (DX-OL) able to host fenretinide (4-HPR) by complexation. In this study, we have investigated the effects of 4-HPR-loaded amphipilic dextrin (DX-OL/4-HPR) in comparison with 4-HPR alone both in vitro on human NB cells and in vivo in pseudometastatic NB models. The haemolysis assay was used as a measure of the potential damage caused by the pharmaceutical formulation in vivo. Pharmacokinetic experiments were performed to assess drug plasma levels in mice treated with free or complexed 4-HPR.
DX-OL/4-HPR exerted a more potent cytotoxic activity on NB cells. Complexed 4-HPR significantly increased the proportion of sub-G1 cells with respect to free 4-HPR. Dextrin derivatives showed no haemolytic activity, indicating their suitability for parenteral administration. DX-OL/4-HPR increased the lifespan and the long-term survival of treated mice over controls. The analysis of drug plasma levels indicates that the complexed drug has a higher AUC due to a reduced clearance from the blood.
Our data suggest that DX-OL/4-HPR is an injectable formulation that is able to improve drug aqueous solubility and bioavailability.
[Show abstract][Hide abstract] ABSTRACT: The retinoid 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) is a polar metabolite of fenretinide (4-HPR) very effective in killing cancer cells of different histotypes, able to inhibit 4-HPR-resistant cell growth and to act synergistically in combination with the parent drug. Unlike 4-HPR and other retinoids, 4-oxo-4-HPR inhibits tubulin polymerization, leading to multipolar spindle formation and mitotic arrest. Here we investigated whether 4-oxo-4-HPR, like 4-HPR, triggered cell death also via reactive oxygen species (ROS) generation and whether its antimicrotubule activity was related to a ROS-dependent mechanism in ovarian (A2780), breast (T47D), cervical (HeLa) and neuroblastoma (SK-N-BE) cancer cell lines.
We provided evidence that 4-oxo-4-HPR, besides acting as an antimicrotubule agent, induced apoptosis through a signaling cascade starting from ROS generation and involving endoplasmic reticulum (ER) stress response, Jun N-terminal Kinase (JNK) activation, and upregulation of the proapoptotic PLAcental Bone morphogenetic protein (PLAB). Through time-course analysis and inhibition of the ROS-related signaling pathway (upstream by vitamin C and downstream by PLAB silencing), we demonstrated that the antimitotic activity of 4-oxo-4-HPR was independent from the oxidative stress induced by the retinoid. In fact, ROS generation occurred earlier than mitotic arrest (within 30 minutes and 2 hours, respectively) and abrogation of the ROS-related signaling pathway did not prevent the 4-oxo-4-HPR-induced mitotic arrest.
These data indicate that 4-oxo-4-HPR anticancer activity is due to at least two independent mechanisms and provide an explanation of the ability of 4-oxo-4-HPR to be more potent than the parent drug and to be effective also in 4-HPR-resistant cell lines. In addition, the double mechanism of action could allow 4-oxo-4-HPR to efficiently target tumour and to eventually counteract the development of drug resistance.
[Show abstract][Hide abstract] ABSTRACT: Fenretinide (4-HPR), a synthetic retinoid currently used in clinic for cancer therapy and prevention, markedly lowers plasma retinol levels, an effect associated with nyctalopia. Our aim was to investigate the relationship between 4-HPR pharmacokinetics, plasma retinol reduction and incidence of nyctalopia.
Children with neuroblastoma, participating in a phase I trial, were treated with oral 4-HPR, once a day for 28-day courses followed by a 7-day drug interruption, with escalating dose levels from 100 to 4,000 mg/m(2) per day. Blood samples were collected at baseline and up to 48 h after the 1st (50 patients) and 28th (41 patients) administration, and the plasma concentrations of 4-HPR and retinol were measured by HPLC.
After the first administration, nadir retinol concentrations were reached at 16-20 h post-dosing; the extent of retinol reduction was related to 4-HPR dose and plasma concentrations as well as to pretreatment retinol concentrations. After repeated treatments, nadir retinol concentrations (10-20% of baseline values) were maintained during the 24 h dosing interval and were similar at all doses; the extent of retinol reduction was significantly (r = 0.97, P < 0.0001) related to pretreatment retinol concentrations. After a single dose, the relationship between 4-HPR pharmacokinetics and pharmacodynamics indicated a counterclockwise hysteresis suggesting the presence of an effect compartment. At steady state, the hysteresis collapsed suggesting that the 4-HPR concentrations in plasma and in the effect compartments were in equilibrium. Nyctalopia was not related to the administered dose, but was significantly associated (P = 0.05) with lower nadir retinol concentrations (0.11 +/- 0.012 vs. 0.17 +/- 0.015 microM).
During 4-HPR chronic treatment, plasma retinol reduction is not proportional to the dose. Plasma retinol levels of 0.11 microM could be considered as a safety biomarker in children with neuroblastoma. Finally, since initial retinol levels strongly predict the extent of retinol reduction, retinol decrease could be used to monitor 4-HPR compliance.
Full-text · Article · Oct 2010 · Cancer Chemotherapy and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: The retinoid 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR), a metabolite of fenretinide (4-HPR) present in plasma of 4-HPR-treated patients, is very effective in inducing growth inhibition and apoptosis in several cancer cell lines. 4-Oxo-4-HPR and 4-HPR have different mechanisms of action because 4-oxo-4-HPR, unlike 4-HPR, causes marked cell accumulation in G2-M phase. Here, we investigated the molecular events involving 4-oxo-4-HPR-induced cell cycle perturbation in ovarian (A2780 and IGROV-1) and breast (T47D, estrogen receptor+ and BT-20, estrogen receptor-) cancer cells. 4-Oxo-4-HPR induced a delay of mitosis (with mitotic index increasing 5- to 6-fold in all cell lines) without progression beyond the anaphase, as shown by cyclin B1 expression. 4-Oxo-4-HPR induced multipolar spindle formation and phosphorylation of BUBR1, resulting in activation of the spindle checkpoint. Multipolar spindles were not due to impairment of pole-focusing process, loss of centrosome integrity, or modulation of the expression levels of molecules associated with spindle aberrations (Kif 1C, Kif 2A, Eg5, Tara, tankyrase-1, centractin, and TOGp). We show here that 4-oxo-4-HPR targets microtubules because, in treated cells, it interfered with the reassembly of cold-depolymerized spindle microtubules and decreased the polymerized tubulin fraction. In cell-free assays, 4-oxo-4-HPR inhibited tubulin polymerization (50% inhibition of microtubule assembly at 5.9 micromol/L), suggesting a direct molecular interaction with tubulin. In conclusion, by showing that 4-oxo-4-HPR causes mitotic arrest through antimicrotubule activities, we delineate a new molecular mechanism for a retinoid.
No preview · Article · Dec 2009 · Molecular Cancer Therapeutics
[Show abstract][Hide abstract] ABSTRACT: Fenretinide [N-(4-hydroxyphenyl)-retinamide (4HPR)] is a synthetic retinoid with antitumor activity that induces apoptosis in various types of cancer cell. We showed previously that 4HPR upregulates the proapoptotic gene placental bone morphogenetic protein (PLAB), which is a mediator of 4HPR-induced apoptosis in ovarian cancer cells. Here, we investigated the signaling cascade involving PLAB that mediates the apoptotic effect. In 4HPR-sensitive ovarian cancer cells, 4HPR-induced reactive oxygen species (ROS) are involved in PLAB upregulation and apoptosis, both events abrogated by the antioxidants vitamin C and butylated hydroxyanisole. We analyzed the expression and activation of endoplasmic reticulum (ER) stress-associated molecules and show that 4HPR-induced ER stress is a consequence of ROS generation. Salubrinal, an ER stress inhibitor, abrogated 4HPR-induced PLAB upregulation and protected the cells from apoptosis. Downstream of ROS generation and ER stress, 4HPR activated c-Jun N-terminal kinase (JNK), which was inhibited by vitamin C and salubrinal. The JNK inhibitor SP600125 reduced 4HPR-induced PLAB upregulation, by decreasing PLAB mRNA half-life, and protected the cells from apoptosis. These data indicate that 4HPR-induced PLAB upregulation occurs downstream of a signaling cascade involving ROS generation, ER stress induction and JNK activation and that these steps are mediators of 4HPR-induced apoptosis.
[Show abstract][Hide abstract] ABSTRACT: The role of retinol (vitamin A) in breast cancer prognosis has never been investigated in postmenopausal women. We prospectively assessed the long-term prognostic role of retinol plasma levels in a cohort of postmenopausal breast cancer patients. Patients and
We investigated 208 women self-reported as postmenopausal operated on for T(1-2)N(0)M(0) breast cancer who participated in a chemoprevention trial as controls and never received chemotherapy or hormone therapy. Plasma samples were collected 3 months (median) after surgery and assayed within 3 weeks for retinol. Minimum and median potential follow-up were 12 and 15 years, respectively. The main analyses were on all women and on a subgroup ages >or=55 years, assumed too old to be in perimenopause. The main end point was breast cancer death. Breast cancer survival was estimated by the Kaplan-Meier method. The hazard ratios of breast cancer death by retinol level were estimated by Cox models stratified for age, where relevant, and recruitment period, and adjusted for tumor size and histology.
At 12 years, patients with low retinol (<2.08 micromol/L, median of distribution) had lower breast cancer survival than those with high retinol (log-rank P = 0.052); the difference was significant for women >or=55 years (log-rank P = 0.006). The adjusted hazard ratios for low versus high retinol were 2.11 (95% confidence interval, 1.08-4.14) for all women and 3.58 (95% confidence interval, 1.50-8.57) for those >or=55 years.
Low plasma retinol strongly predicts poorer prognosis in postmenopausal breast cancer patients. Retinol levels should be determined as part of the prognostic workup.
No preview · Article · Jan 2009 · Cancer Epidemiology Biomarkers & Prevention
[Show abstract][Hide abstract] ABSTRACT: Pharmacokinetic data on fenretinide (4-HPR) are scant, thus limiting the rational use of the drug. We investigated the pharmacokinetics of 4-HPR and its active metabolite 4-oxo-fenretinide (4-oxo-4-HPR).
Pharmacokinetics were assessed in 18 children (3 for each dose) with neuroblastoma who received oral 4-HPR once daily for 28 days at the doses of 100, 300, 400, 600, 1,700 and 4,000 mg/m(2)/day. 4-HPR and 4-oxo-4-HPR were determined by HPLC in plasma collected up to 48 h after the first and 28th administration.
After single administration, 4-HPR mean C (max) ranged from 0.9 to 6.6 microM and these concentrations roughly doubled at steady state (range 1.6-14.5 microM). 4-HPR mean t (1/2) was 22 h. 4-HPR pharmacokinetics were linear in the dose range 100-1,700 mg/m(2); less than dose-proportional increase in exposure was found at 4,000 mg/m(2). At steady state, pharmacologically relevant plasma concentrations (range 0.7-10 microM and 0.4-5 microM for 4-HPR and 4-oxo-4-HPR, respectively) were maintained during the 24 h dosing interval in the dose range 300-4,000 mg/m(2).
4-HPR pharmacokinetics supports once-daily dosing. Steady state concentrations of 4-HPR and 4-oxo-4-HPR in children with neuroblastoma are in line with those found to have in vitro growth inhibitory effects in neuroblastoma cells.
No preview · Article · Oct 2008 · Cancer Chemotherapy and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: High endogenous testosterone is associated with increased breast cancer (BC) risk. We designed this study specifically to assess the long-term prognostic role of testosterone in a cohort of postmenopausal BC patients.
We considered 194 postmenopausal women, operated on for early BC (T1-2N0M0), who never received chemotherapy or hormonal therapy, and who participated in a fenretinide BC prevention trial as untreated controls. Blood samples were collected 3 months (median) after surgery; plasma samples, stored at -80 degrees C, were radioimmunoassayed for testosterone. Median follow-up was 14 years. The main end point was any cancer event. Event-free survival was estimated by the Kaplan-Meier method. Hazard ratios (HRs) of events by testosterone level were estimated by the Cox model, adjusting for age, tumor size, and histology.
Patients with high testosterone (> or = 0.40 ng/mL, median of distribution) had significantly lower event-free survival than those with low testosterone (log-rank P = .004). The adjusted HR of patients with high versus low testosterone was 2.05 (95% CI, 1.28 to 3.27). High testosterone was also associated with a significantly higher risk of BC events (relapse and second primary) with an adjusted HR of 1.77 (95% CI, 1.06 to 2.96). Eleven second primaries (non-BC) occurred in the high-testosterone group, four in the low-testosterone group.
High plasma testosterone strongly predicts poorer prognosis in postmenopausal BC patients not administered adjuvant therapy. Testosterone levels should be determined as part of the prognostic work-up.
Full-text · Article · Aug 2007 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: Fenretinide (4-HPR) is a synthetic retinoid with antitumor activity, which induces apoptosis in cancer cell lines of different histotypes. To identify genes contributing to its apoptotic activity in ovarian cancer cells, we monitored, by cDNA arrays, gene expression changes after 4-HPR exposure in A2780, a human ovarian carcinoma cell line sensitive to the retinoid. Among the differentially expressed transcripts, PLAcental Bone morphogenetic protein (PLAB), a proapoptotic gene, was the most highly induced. In a panel of ovarian carcinoma cell lines with different 4-HPR sensitivities, PLAB upregulation was associated with cellular response to 4-HPR, its overexpression increased basal apoptosis and its silencing by small interfering RNA decreased the ability of 4-HPR to induce apoptosis. PLAB induction by 4-HPR was p53- and EGR-1 independent and was regulated, at least in part, by increased stability of PLAB mRNA. PLAB up-modulation by 4-HPR also occurred in vivo: in ascitic cells collected from patients with ovarian cancer before and after 4-HPR treatment, PLAB was upmodulated in 2/4 patients. Our results in certain ovarian cancer cell lines indicate a role for PLAB as a mediator of 4-HPR-induced apoptosis. The correlation of increased PLAB in vivo with antitumor activity remains to be established.
[Show abstract][Hide abstract] ABSTRACT: To evaluate study feasibility, toxicity, drug concentrations, and activity of escalating doses of the synthetic retinoid fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] in ovarian cancer by measuring serum CA125 and cytomorphometric biomarkers in cancer cells collected from ascitic fluid before and after treatment.
Twenty-two naive patients with ascitic ovarian cancer were treated with escalating doses of 4-HPR at 0, 400, 600, and 800 mg/d for 1 to 4 weeks before surgery. Changes in the proportion of proliferating cells expressed by Ki67 and computer-assisted cytomorphometric variables (nuclear area, DNA index, and chromatin texture) were determined in ascitic cells. Drug levels were measured by high-performance liquid chromatography.
Doses up to 800 mg/d were well tolerated, and no adverse reactions occurred. There was no effect of 4-HPR on changes in serum CA125, Ki67 expression, which were assessed in 75% of subjects, and cytomorphometric variables, which were assessed in 80% of subjects. Plasma retinol levels were significantly lower in affected women than healthy donors. 4-HPR plasma concentrations increased slightly with increasing doses and attained a 1.4 micromol/L concentration with 800 mg/d. Drug levels in malignant ascitic cells and tumor tissue were higher than in plasma but were 50 and 5 times lower, respectively, than in carcinoma cells treated in vitro with 1 micromol/L 4-HPR.
Cell biomarkers can be measured in ascitic cells to assess drug activity. Under our experimental conditions, 4-HPR did not show activity in advanced ovarian cancer cells. However, clinical evidence supports further investigation of fenretinide for ovarian cancer prevention.
No preview · Article · Nov 2006 · Cancer Epidemiology Biomarkers & Prevention
[Show abstract][Hide abstract] ABSTRACT: 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) is a recently identified metabolite of fenretinide (4-HPR). We explored the effectiveness of 4-oxo-4-HPR in inducing cell growth inhibition in ovarian, breast, and neuroblastoma tumor cell lines; moreover, we investigated the molecular events mediating this effect in two ovarian carcinoma cell lines, one sensitive (A2780) and one resistant (A2780/HPR) to 4-HPR. 4-oxo-4-HPR was two to four times more effective than 4-HPR in most cell lines, was effective in both 4-HPR-sensitive and 4-HPR-resistant cells, and, in combination with 4-HPR, caused a synergistic effect. The tumor growth-inhibitory effects of 4-oxo-4-HPR seem to be independent of nuclear retinoid receptors (RAR), as indicated by the failure of RAR antagonists to inhibit its effects and by its poor ability to bind and transactivate RARs. Unlike 4-HPR, which only slightly affected the G(1) phase of the cell cycle, 4-oxo-4-HPR caused a marked accumulation of cells in G(2)-M. This effect was associated with a reduction in the expression of regulatory proteins of G(2)-M (cyclin-dependent kinase 1 and cdc25c) and S (cyclin A) phases, and with an increase in the expression of apoptosis-related proteins, such as p53 and p21. Apoptosis was induced by 4-oxo-4-HPR in both 4-HPR-sensitive and 4-HPR-resistant cells and involved activation of caspase-3 and caspase-9 but not caspase-8. We also showed that 4-oxo-4-HPR, similarly to 4-HPR, increased reactive oxygen species generation and ceramide levels by de novo synthesis. In conclusion, 4-oxo-4-HPR is an effective 4-HPR metabolite that might act as therapeutic agent per se and, when combined with 4-HPR, might improve 4-HPR activity or overcome 4-HPR resistance.
[Show abstract][Hide abstract] ABSTRACT: We assessed the efficacy of fenretinide at preventing relapses, new lesions and carcinomas after surgical excision of oral leukoplakia. In a controlled multicenter study, 170 patients operated on for oral leukoplakias with benign postoperative histology were randomized to 200 mg fenretinide daily for 1 year vs. no intervention. Preliminary analysis indicated that fenretinide had good tolerability and was effective at preventing relapses and new lesions during treatment. Analysis after 5-year follow-up suggested that fenretinide protected against relapses and new lesions up to 19 months after randomization, with both limits of the 95% hazard ratio CI for fenretinide vs. control below 1 for 7 months after randomization. There was also a protective effect against all first events, including cancer, for 25 months, with both limits of the 95% CI below 1 up to 11 months after randomization. Subsequently, risk ratio estimates were unstable. Fenretinide was well tolerated and effective at preventing relapses and new leukoplakias during treatment and after. The trial had to be stopped prematurely for very low recruitment and had insufficient power to reveal any protective effect against oral carcinoma; nevertheless, continuing studies on this promising chemopreventive are justified.
Full-text · Article · Jul 2005 · International Journal of Cancer
[Show abstract][Hide abstract] ABSTRACT: The synthetic retinoid fenretinide (4-HPR) exhibits preventive and therapeutic activity against ovarian tumors. An unidentified polar metabolite was previously found in 4-HPR-treated subjects and in A2780 human ovarian carcinoma cells continuously treated with 4-HPR (A2780/HPR). The metabolite and the enzyme involved in its formation in tumor cells are herein identified.
The metabolite was identified by mass spectrometry in A2780/HPR cell extracts and in plasma from 11 women participating in a phase III trial and treated with 200 mg/d 4-HPR for 5 years. The expression of proteins involved in retinoid metabolism and transport, cytochrome P450 26A1 (CYP26A1), cellular retinol-binding protein I (CRBP-I), and cellular retinoic acid-binding protein I and II (CRABP-I, CRABP-II) were evaluated in tumor cells by reverse transcription-PCR and Western blot analyses. Overexpression of CYP26A1 and retinoic acid receptors (RARs) in A2780 cells were obtained by cDNAs transfection.
The polar metabolite was 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) i.e., an oxidized form of 4-HPR with modification in position 4 of the cyclohexene ring. 4-oxo-4-HPR plasma levels were slightly lower (0.52 +/- 0.17 micromol/L) than those of the parent drug (0.84 +/- 0.53 micromol/L) and of the already identified metabolite N-(4-methoxyphenyl)retinamide (1.13 +/- 0.85 micromol/L). In A2780/HPR cells continuously treated with 4-HPR and producing 4-oxo-4-HPR, CYP26A1 and CRBP-I were markedly up-regulated compared with A2780 untreated cells. In A2780 cells, not producing 4-oxo-4-HPR, overexpression of CYP26A1 caused formation of 4-oxo-4-HPR, which was associated with no change in 4-HPR sensitivity. Moreover, the addition of 4-oxo-4-HPR to A2780 cells inhibited cell proliferation. Elevated levels of CYP26A1 protein and metabolism of 4-HPR to 4-oxo-4-HPR were found in A2780 cells transfected with RARbeta and to a lesser extent in those transfected with RARgamma.
A new metabolite of 4-HPR, 4-oxo-4-HPR, present in human plasma and in tumor cells, has been identified. The formation of this biologically active metabolite in tumor cells was due to CYP26A1 induction and was influenced by RAR expression. Moreover evidence was provided that 4-HPR up-modulates the expression of CRBP-I transcript, which is lost during ovarian carcinogenesis.
No preview · Article · Oct 2004 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Fenretinide (HPR), a synthetic retinoid that exhibits lower toxicity than other retinoids, has shown preventive and therapeutic activity against ovarian tumors. Although the growth inhibitory effects of HPR have been ascribed to its ability to induce apoptosis, little is known about the molecular mechanisms involved. Since the proto-oncogene c-Fos has been implicated in apoptosis induction, we analyzed its role in mediating HPR response in a human ovarian carcinoma cell line (A2780) sensitive to HPR apoptotic effect. In these cells, HPR treatment caused induction of c-Fos expression, whereas such an effect was not observed in cells made resistant to HPR-induced apoptosis (A2780/HPR). Moreover, in a panel of other human ovarian carcinoma cell lines, c-Fos inducibility and HPR sensitivity were closely associated. Ceramide, which is involved in HPR-induced apoptosis, was also involved in c-Fos induction because its upregulation by HPR was reduced by fumonisin B(1), a ceramide synthase inhibitor. The causal relationship between c-Fos induction and apoptosis was established by the finding of an increased apoptotic rate in cells overexpressing c-Fos. Similarly to that observed for c-Fos expression, HPR treatment increased c-Jun expression in HPR-sensitive but not in HPR-resistant cells, suggesting the involvement of the transcription factor activating protein 1 (AP-1) in HPR-induced apoptosis. In gene reporter experiments, HPR stimulated AP-1 transcriptional activity and potentiated the AP-1 activity induced by 12-tetradecanoylphorbol 13-acetate. Furthermore, inhibition of AP-1 DNA binding, by transfecting A2780 cells with a dominant-negative Fos gene, caused decreased sensitivity to HPR apoptotic effects. Overall, the results indicate that c-Fos plays a role in mediating HPR-induced growth inhibition and apoptosis in ovarian cancer cells and suggest that c-Fos regulates these processes as a member of the AP-1 transcription factor.
Preview · Article · Apr 2004 · Cell Death and Differentiation
[Show abstract][Hide abstract] ABSTRACT: High circulating insulin-like growth factor (IGF) -I and/or low IGF-binding protein (IGFBP) -3 levels are associated with increased breast cancer risk in unaffected premenopausal women. We determined whether IGF-I and IGFBP-3 predict second breast cancer risk, and whether their changes during fenretinide explain observed reductions in second breast cancer in women </=50 years of age.
Within a Phase III trial, we measured baseline and 1-year levels of IGF-I, IGFBP-3, and their ratio in 302 subjects on fenretinide and 220 controls who provided plasma samples. The prognostic effect of IGF-I and IGFBP-3, and the surrogate effect of IGF-I during fenretinide were assessed by Cox models after 9.4 years.
Among controls, high IGF-I and low IGFBP-3 were associated with elevated second breast cancer risk [top versus bottom tertile, IGF-I, hazard ratio (HR) = 1.94, 95% confidence interval (CI), 0.87-4.31, P = 0.105; and IGFBP-3, HR = 0.40, 95% CI, 0.18-0.93, P = 0.033]. Fenretinide induced reductions of IGF-I, IGFBP-3, and IGF-I:IGFBP-3 of 8% (95% CI, 2-12%; P = 0.004), 3% (95% CI, 1-5%; P = 0.002), and 5% (95% CI, 0-10%; P = 0.050), respectively. Second breast cancer risk was reduced by 39% (HR = 0.61; 95% CI, 0.40-0.94; P = 0.026). The percentage of treatment effect explained by IGF-I and IGF-I:IGFBP-3 reductions were 4.8% (95% CI, 0.8-28.9%) and 3.1% (95% CI, 0.5-20.8%), respectively.
Fenretinide induced a moderate reduction of IGF-I, which marginally explains observed cancer risk reductions in women </=50 years of age. In this age group high IGF-I and particularly low IGFBP-3 levels predict second breast cancer risk.
Full-text · Article · Oct 2003 · Clinical Cancer Research