adarotene and Ovarian-Neoplasms

E-3-(4'-Hydroxy-3'-adamantylbiphenyl-4-yl) acrylic acid (ST1926) is a novel oral synthetic adamantyl retinoid derivative, now under early clinical investigation in patients with ovarian cancer. To investigate the pharmacokinetics of this new antitumor agent in human plasma, we developed and validated a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method based on the addition of ST2222 as internal standard and simple protein precipitation with methanol. The method requires a small volume of sample (100microL); it is rapid and selective, allowing a good resolution of peaks from the plasma matrix in 9min. The method offers high recovery (>90%), it is sensitive, precise and accurate with overall precision expressed as CV% less than 8.2%. We set the lower limit of quantitation at 20.0ng/mL and validated the assay up to the concentration of 1000.0ng/mL. The present method has been successfully applied to study ST1926 pharmacokinetics in patients with advanced ovarian cancer in a Phase I trial, administering the drug orally for five consecutive days. During analysis of the study samples, it became evident the presence of glucuroconjugates of the parent compound, established by LC-Orbitrap MS. Preliminary results show low and variable drug absorption in patients, with extensive glucuroconjugation influencing the bioavailability of ST1926.

Topics: Adamantane; Antineoplastic Agents; Calibration; Chromatography, High Pressure Liquid; Cinnamates; Drug Stability; Female; Humans; Linear Models; Ovarian Neoplasms; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry

The synthetic atypical retinoids containing an adamantyl group exhibit antiproliferative or proapoptotic activities. Apoptosis induction is a dose-dependent effect independent of retinoid receptors. We have reported that induction of apoptosis by the atypical retinoid, ST1926, is associated with early manifestations of genotoxic stress. Indeed, in this study performed in ovarian carcinoma cells, we show that exposure to ST1926 resulted in an increase of early markers of DNA damage, including ATM and H2AX phosphorylation. In addition, we found that a novel histone deacetylase (HDAC) inhibitor (RC307) was able to enhance sensitivity of ovarian carcinoma cells to ST1926. Under conditions where single-agent treatment caused only antiproliferative effects, the combination of the atypical retinoid and HDAC inhibitor resulted in marked apoptotic cell death with a more rapid onset in wild-type p53 ovarian carcinoma cells. The sensitization to ST1926-induced apoptosis was associated with an enhanced DNA damage response, because a prolonged expression of DNA damage markers (e.g., H2AX, p53 and RPA-2 phosphorylation) and a marked activation of DNA damage checkpoint kinases (in particular, phosphorylation of Chk1) were observed indicating an accumulation of DNA damage by the ST1926/HDAC inhibitor combination. The study provides additional support to the role of DNA damage as a primary event leading to the activation of apoptosis in ovarian carcinoma cells by adamantyl retinoids and documents the potential therapeutic efficacy of the combination of ST1926 and HDAC inhibitors of the novel series.

Topics: Adamantane; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cinnamates; DNA Damage; Enzyme Inhibitors; Female; Histone Deacetylases; Humans; In Situ Nick-End Labeling; Mice; Mice, Nude; Ovarian Neoplasms; Retinoids; Xenograft Model Antitumor Assays

The novel adamantyl retinoid ST1926 is a potent inducer of apoptosis in ovarian carcinoma cells. Since the pro-apoptotic effect is associated with activation of p53, in this study we have investigated the efficacy of combination of ST1926 with cisplatin, a DNA-damaging agent that is known to induce p53-dependent apoptosis.. The efficacy of ST1926 and its combination with cisplatin was evaluated in human ovarian carcinoma models, including resistant tumors.. Oral treatment with ST1926 alone caused a marginal tumor growth inhibition (<50%), but the combination with cisplatin resulted in an improved efficacy, most evident in terms of tumor growth delay without a substantial increase of toxicity. The combination therapy achieved the best effects against the HOC18 ovarian carcinoma tumor, resulting in an appreciable number of animals without evidence of disease at the end of the experiment. In contrast to the marginal effect of ST1926 alone against the subcutaneous-growing tumors, loco-regional (intraperitoneal) treatment achieved a marked increase of survival of animals with ascitic IGROV-1 tumor.. The present results document the efficacy of the combination of cisplatin with ST1926 and provide a rational basis for the design of novel, well-tolerated platinum-based treatment approaches in human ovarian carcinoma.

Topics: Adamantane; Animals; Antineoplastic Combined Chemotherapy Protocols; Cinnamates; Cisplatin; Female; Humans; Mice; Mice, Nude; Ovarian Neoplasms; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Strategies targeting apoptotic pathways may have relevance to improve the efficacy of antitumor therapy. Because synthetic atypical retinoids are potent inducers of apoptosis, there is an increasing interest in exploiting their potential in novel therapeutic approaches. In the present study, we have investigated the cellular effects of the combination of a novel atypical retinoid, ST1926, and the epidermal growth factor receptor inhibitor ZD1839. The results indicated a synergistic interaction between the two drugs associated with a dramatic enhancement of apoptotic response, up-regulation of the cell death receptor DR5, and caspase 8 activation. Other molecular events induced by the cotreatment included (a) a stabilization of the ST1926-induced genotoxic stress detected by formation of phosphorylated gamma-H2AX foci and (b) a complete inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation associated with activation of the proapoptotic protein BAD (i.e., inhibition of phosphorylation on Ser112). In addition, ZD1839 itself inhibited survival pathways by causing a partial dephosphorylation of Akt and a marked down-regulation of survivin. The role of ERK-mediated survival pathways in the cellular response to the drug combination was further supported by the counteracting effect of stimulation of survival pathways by an alternative receptor tyrosine kinase and by the use of a specific inhibitor of the ERK pathway. In conclusion, the results support that the survival pathways activated by epidermal growth factor receptor are determinants of the cell susceptibility to ST1926-induced apoptosis and lowering survival signals may increase the cellular sensitivity to the atypical retinoid. The favorable pharmacologic profiles of both ST1926 and ZD1839 suggest that the combination of these well-tolerated agents may have therapeutic potential.

Topics: Adamantane; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma, Squamous Cell; Caspase 8; Caspases; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Cinnamates; DNA Damage; Drug Synergism; Enzyme Activation; ErbB Receptors; Female; Gefitinib; Humans; Ovarian Neoplasms; Quinazolines; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; Signal Transduction; Vulvar Neoplasms

To understand the molecular mechanisms mediating apoptosis induction by a novel atypical retinoid, ST1926, the cellular response to drug treatment was investigated in IGROV-1 ovarian carcinoma cells carrying wild-type p53 and a cisplatin-resistant p53 mutant subline (IGROV-1/Pt1). Despite a similar extent of drug-induced DNA strand breaks, the level of apoptosis was substantially higher in p53 wild-type cells. p53 activation and early upregulation of p53-target genes were consistent with p53-dependent apoptosis in IGROV-1 cells. Stress-activated protein kinases were activated in both cell lines in response to ST1926. This event and activation of AP-1 were more pronounced in IGROV-1/Pt1 cells, in which the modulation of DNA repair-associated genes suggests an increased ability to repair DNA damage. Inhibition of JNK or p38 stimulated ST1926-induced apoptosis only in IGROV-1 cells, whereas inhibition of ERKs enhanced apoptosis in both the cell lines. Such a pattern of cellular response and modulation of genes implicated in DNA damage response supports that the genotoxic stress is a critical event mediating drug-induced apoptosis. The results are consistent with apoptosis induction through p53-dependent and -independent pathways, regulated by MAP kinases, which likely play a protective role.

Topics: Adamantane; Antineoplastic Agents; Apoptosis; Blotting, Western; Carcinoma; Caspases; Cell Division; Cell Line, Tumor; Cinnamates; DNA Damage; DNA Repair; DNA, Neoplasm; Enzyme Activation; Female; Gene Expression Regulation, Neoplastic; Humans; Mitogen-Activated Protein Kinases; Molecular Structure; Ovarian Neoplasms; Proliferating Cell Nuclear Antigen; Stress, Physiological; Transcription Factor AP-1; Tumor Suppressor Protein p53

The novel atypical retinoid E-3-(4'-hydroxy-3'-adamantylbiphenyl-4-yl)acrylic acid (ST1926, 4) exhibited a potent antiproliferative activity on a large panel of human tumor cells. Despite almost complete loss of ability to activate RARs, the compound was an effective apoptosis inducer and surprisingly produced DNA damage, that likely contributes to the proapoptotic activity. Following oral administration, 4 was well tolerated and caused tumor growth inhibition in the ovarian carcinoma, A2780/DX, and in the human melanoma, MeWo, growing in nude mice, thus supporting the therapeutic interest of the novel agent.

Topics: Adamantane; Animals; Antineoplastic Agents; Apoptosis; Cinnamates; DNA Damage; Drug Screening Assays, Antitumor; Female; Humans; Melanoma; Mice; Mice, Nude; Ovarian Neoplasms; Protein Isoforms; Receptors, Retinoic Acid; Retinoids; Structure-Activity Relationship; Transfection; Transplantation, Heterologous; Tumor Cells, Cultured