Agnes Jaeger-Lansky

mTOR inhibition by everolimus counteracts VEGF induction by sunitinib and improves anti-tumor activity against gastric cancer in vivo.

VEGF receptor blockage has been reported to increase serum VEGF. We hypothesized that mTOR inhibition by everolimus counteracts VEGF induction by sunitinib resulting in an improved anti-tumor activity of sunitinib. In vitro, sunitinib in combination with everolimus did not outperform the respective monotherapies. In vivo, monotherapies reduced tumor growth by 60%, whereas the combination of sunitinib and everolimus led to an almost complete tumor growth inhibition. This superior anti-tumor activity coincided with attenuation of VEGF peaks. In conclusion mTOR inhibition by everolimus counteracts VEGF induction by sunitinib and results in significant reduction of tumor burden and long-lasting tumor growth control.

Gastric Cancer Growth Control by BEZ235 In Vivo Does Not Correlate with PI3K/mTOR Target Inhibition but with [18F]FLT Uptake

Purpose: In this study, we tested the antitumor activity of the dual phosphoinositide 3-kinase (PI3K)/mTOR inhibitor BEZ235 against gastric cancer in vitro and in vivo. Experimental Design: Gastric cancer cell lines (N87, MKN45, and MKN28) were incubated with BEZ235 and assessed for cell viability, cell cycle, and PI3K/mTOR target inhibition. In vivo, athymic nude mice were inoculated with N87, MKN28, or MKN45 cells and treated daily with BEZ235. 3′-Deoxy-3′-[18F]fluorothymidine ([18F]FLT) uptake was measured via small animal positron emission tomography (PET). Results:In vitro, BEZ235 dose dependently decreased the cell viability of gastric cancer cell lines. The antiproliferative activity of BEZ235 was linked to a G1 cell-cycle arrest. In vivo, BEZ235 treatment resulted in PI3K/mTOR target inhibition as shown by dephosphorylation of AKT and S6 protein in all xenograft models. However, BEZ235 treatment only inhibited tumor growth of N87 xenografts, whereas no antitumor effect was observed in the MKN28 and MKN45 xenograft models. Sensitivity to BEZ235 in vivo correlated with downregulation of the proliferation marker thymidine kinase 1. Accordingly, [18F]FLT uptake was only significantly reduced in the BEZ235-sensitive N87 xenograft model as measured by PET. Conclusion: In conclusion, in vivo sensitivity of gastric cancer xenografts to BEZ235 did not correlate with in vitro antiproliferative activity or in vivo PI3K/mTOR target inhibition by BEZ235. In contrast, [18F]FLT uptake was linked to BEZ235 in vivo sensitivity. Noninvasive [18F]FLT PET imaging might qualify as a novel marker for optimizing future clinical testing of dual PI3K/mTOR inhibitors. Clin Cancer Res; 17(16); 5322–32. ©2011 AACR.

Cytokeratin-19 as a biomarker in urine and in serum for the diagnosis of endometriosis--a prospective study.

Abstract Endometriosis compromises the quality of life of countless women worldwide and is a leading cause of disability. Clinical symptoms of endometriosis can be very heterogeneous leading to a long interval between onset of symptoms and surgical diagnosis. A noninvasive, rapid diagnostic test is urgently needed. In this prospective study, we evaluated the usefulness of Cytokeratin-19 (CK19) as a biomarker for the diagnosis of endometriosis through urine and serum ELISA. 76 reproductive-aged women undergoing laparoscopy for benign conditions were included to this study and divided into two groups by the presence (n = 44) or absence (n = 32) of endometriosis. There was no statistically significant correlation between the concentration of CK19 in urine (p = 0.51) or in serum (p = 0.77) and the diagnosis of endometriosis. Assigning the samples to the proliferative or secretory cycle stage did not sufficiently lower the p values. In this study, the promising data reported in the recent literature about CK19 serving as a sufficient biomarker for endometriosis could not be verified when tested in a larger sample size. Further studies are warranted to explore the usefulness of CK19 in the diagnosis of endometriosis.

What do women with gynecologic cancer know about HPV and their individual disease? A pilot study

BackgroundThe vaccinations against human papilloma virus (HPV) are highly effective in preventing persistent infection. The level of knowledge about HPV and the consequences of an infection with this virus are low in the general population and in patients who suffer from HPV-associated diseases. We aimed to compare the level of knowledge about HPV and about the women’s individual malignant disease between women with and without HPV-associated gynecologic cancer as well as the knowledge about individual malignant diseases.MethodsIn a pilot study, 51 women with HPV-related cancer (cervical cancer: n = 30; vulvar or vaginal cancer: n = 21) and 60 women with non-HPV associated gynecologic malignancies (ovarian cancer: n = 30; endometrial cancer, n = 30) were included. They answered a questionnaire including questions about personal medical history, risk factors for cancer development, and HPV.ResultsThe general level of knowledge of the term “HPV” was low (29.7%, 33/111) and it was similar in patients with HPV-related and non-HPV-associated cancer (18/60, 30.0% vs. 15/51, 29.4%, respectively; p = 1.000). When asked about their disease, 80% (24/30) of women with ovarian cancer correctly named their diagnosis, followed by women with cervical cancer (73.3%, 22/30), endometrial cancer (70%, 21/30) and vaginal or vulvar cancer (42.9%, 9/21; p = 0.008).ConclusionThe level of knowledge about HPV and the malignant diseases the patient suffered from was low. This applied even to patients with HPV associated malignancies.

Effects of vatalanib on tumor growth can be potentiated by mTOR blockade in vivo

The vascular endothelial growth factor (VEGF) is a central mediator of tumor-induced angiogenesis. Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, decreases VEGF-secretion of cancer cells. Vatalanib is a selective inhibitor of VEGF receptors 1-3. In the present study it was hypothesized that dual inhibition of VEGF signaling by inhibition of VEGF production and VEGF receptor signaling leads to synergistic anti-tumor effects. In vitro, effects of vatalanib and everolimus on cell proliferation, cell cycle, apoptosis and signal transduction were examined in three gastric cancer cell lines. Effects on angiogenesis were assessed using tube formation assays of cultured human umbilical vein endothelial cells (HUVECs). In vivo, the anti-tumor effect of compounds was studied using a gastric cancer xenograft nude mouse model. VEGF of murine origin (mVEGF) and human cancer cell-derived VEGF (hVEGF) were studied separately by specific ELISAs. Tumor vascularization and proliferation were quantified by immunohistochemistry. In vitro, everolimus but not vatalanib decreased gastric cancer proliferation without inducing apoptosis. Vatalanib abolished endothelial cell tube formation, whereas inhibition of tube formation by everolimus was incomplete. In vivo, the combination of vatalanib with everolimus was superior to single agent treatments and reduced tumor size by about 50% relative to everolimus monotherapy (p

BEZ235 impairs gastric cancer growth by inhibition of PI3K/mTOR in vitro and in vivo

Background Gastric cancer at advanced stage of disease is a major health problem and the prognosis with the current therapeutic treatment strategies remains poor. PI3K/mTOR pathway mutations, especially PTEN, PI3K3C and AKT mutations and pS6 overexpression, are found frequently in gastric cancer patients and are linked with poor outcome. Thus, we evaluated the dual PI3K and mTOR inhibitor BEZ235 against gastric cancer in vitro and in vivo.

Abstract 4470: The dual PI3K/mTOR inhibitor BEZ235 impairs gastric cancer growth in vitro and in vivo

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background Gastric cancer is still a major health problem and the prognosis at advanced stage of disease with the current chemotherapeutic treatment strategies remains poor. Therefore novel treatment strategies and molecular targets for gastric cancer therapy are desperately needed. PI3K/mTOR pathway mutations, especially PTEN, PI3K3C and AKT mutations and pS6 overexpression, frequently occur in gastric cancer. Thus, we tested the activity of the dual PI3K and mTOR BEZ235 against gastric cancer in vitro and in vivo. Materials and Methods Three gastric cancer cell lines (N87, Mkn28 and MKN45) were treated with BEZ235 (20-80nM) and assessed for cell viability, cell death and cell cycle via celltiter blue and FACS analysis, respectively. PI3K/mTOR protein target modulation was measured by Western blotting. For in vivo studies athymic nude mice were inoculated with N87 or Mkn45 cells bilaterally and treated daily with 20 or 40mg/kg BEZ235. Results In vitro, treatment of gastric cancer cells with 20-80nM BEZ235 decreased cell growth in a dose dependent manner in all cell lines tested (up to −70%). This anti-proliferative activity was accompanied with a G1 cell cycle arrest of gastric cancer cells (up to 75%), whereas no significant levels of cell death were detected. On the molecular level, BEZ235 therapy resulted in a decrease of phosphorylation of AKT and S6 protein at 80nM. Notably, lower concentrations abolished mTOR downstream signalling but had no effect on AKT phosphorylation. In vivo, treatment with 20 and 40mg/kg BEZ235 resulted in a significant anti-tumor effect in a N87 gastric cancer xenograft mouse model. Interestingly, BEZ235 therapy displayed no anti-tumor activity in the MKN45 gastric cancer xenograft mouse model. In both models, we observed similar results in terms of PI3K/mTOR pathway downregulation in xenografts. Conclusion BEZ235 has pronounced anti-tumor activity in gastric cancer cells at low nanomolar range, which is linked with PI3K/mTOR downregulation and G1 cell cycle arrest. In vivo, N87 gastric cancer cells responded to BEZ235 treatment, whereas MKN45 cells were resistant. Thus, in our models in vitro sensitivity of BEZ235 did not predict for in vivo activity. We are currently conducting a microPET mouse study in order to evaluate whether PET is a suitable tool to predict BEZ235 sensitivity in vivo and the results will be presented at the meeting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4470.

Abstract A124: ERCC1 expression correlates with EGFR expression and is regulated by cisplatin, cetuximab, and dasatinib in head and neck cancer cells

Background: ERCC1 has been linked to resistance against platin‐based chemotherapy. Cetuximab sensitizes colorectal cancer cells to oxaliplatin. This sensitization coincides with ERCC1 downregulation, but the link between EGFR and ERCC1 is not fully understood. It is known that treatment with cetuximab inhibits nuclear transport of EGFR and DNA repair in response to irradiation. Moreover, cisplatin treatment results in phosphorylation at Y845 and nuclear transport of EGFR. We intended to investigate the regulation of ERCC1 by cisplatin, cetuximab and dasatinib, a src inhibitor stabilizing EGFR in the membrane, its relevance for chemosensitivity and its correlation with EGFR and its phosphorylation at Y845 in head and neck cancer cells. Material and Methods: In UM‐SCC 14c head and neck cancer cell line, ERCC1, EGFR and EGFR (pY845) expression was determined by western blot and FACS analysis. Cell viability, cell cycle and apoptosis induction was assessed by cell titer blue assay, propidium iodide and caspase 3 staining, respectively. Results: In cell viability assay, combination of cisplatin with cetuximab led to a significant (p Conclusion: 14c cells are sensitized to cisplatin treatment by adding cetuximab. ERCC1 expression correlated with phosphorylation status of EGFR (pY845) following treatment with cisplatin and cetuximab. However, treatment with the src inhibitor dasatinib before adding cisplatin and cetuximab reduced phosphorylation of EGFR (Y845), but increased ERCC1 and EGFR expression. Whether the increase of ERCC1 is a late effect due to transcriptional upregulation of EGFR after dasatinib treatment remains to be determined. However, the dose‐effect relationship and the lack of regulation of ERCC1 expression in peripheral blood leukocytes after treatment with cisplatin and cetuximab support the notion that ERCC1 expression is regulated by EGFR in 14c cells. Further studies elucidating the subcellular transport of EGFR and its transcriptional regulation after dasatinib treatment are ongoing and will be presented. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A124.