Abstract 4235: Anti-proliferative effects of ZR2002, a novel combi-molecule with EGFR/DNA binary targeting properties compared to Gefitinib in glioblastoma cell lines and brain tumor stem cells
Bibliographic record
Abstract
Abstract Glioblastoma multiforme (GBM) is the most aggressive form of primary brain tumor in adults with a survival of only 12-15 months. Brain tumor stem cells (BTSCs) contribute to tumor initiation, progression, chemo- and radioresistance, which accounts for tumor recurrence and treatment failure. Amplification of epidermal growth factor receptor (EGFR) is one of the most common genetic alterations associated with GBM aggressiveness. EGFR variant III (EGFRvIII) is an activating mutation that accounts for 60% of EGFR mutations in patients whose tumors show amplification of wild type EGFR. Despite the evidence that EGFR-induced pathway represents an attractive therapeutic target in GBM, gefitinib (Iressa™, ZD1839), an orally active, selective EGFR-tyrosine kinase inhibitor showed only a limited potency in clinical trials. ZR2002, a prototype of ‘combi-molecule’ capable of generating the binary EGFR/DNA targeting activity without requirement for hydrolytic cleavage has not been tested against BTSC. Given the ability of ZR2002 to concomitantly induce DNA damage and block EGFR-mediated signaling, we hypothesized that it would exert greater anti-proliferative activity than gefitinib in GBM tumor cell lines and BTSCs. To investigate our hypothesis, we used isogenic cell lines: U87EGFR wild-type (wt) and U87EGFRvIII (over-expressing EGFRvIII), U87MG (parental cell line) in addition to T98G, a GBM cell line known to express high levels of EGFR and BTSCs derived from patients newly diagnosed with GBM. BTSCs were cultured as neurospheres in stem cell media supplemented with growth factors (EGF, FGF), heparin and proliferation supplement. We examined the half maximal inhibitory concentration (IC50) of ZR2002 compared to gefitinib using MTT proliferation assay. Our results show that all cell lines tested were resistant to gefitinib when compared to ZR2002, which showed sub-micromolar potency in all tested cell lines following a short 2 h drug exposure. IC50s for T98G, U87-MG and U87-EGFRIII treated with ZR2002 were 0.019 μM, 0.048 μM and 0.073 μM, respectively. We further investigated the effect of ZR2002 in four different BTSC cell lines 48EF, OPK111, OPK164 and OPK161 and showed that the IC50s were in a similar range 0.027 μM, 0.014 μM, 0.089 μM and 0.019 μM, respectively. While GBM cell lines and BTSCs are highly resistant to gefitinib, they showed a greater sensitivity to ZR2002 (IC50 is less than 0.1 μM). These findings pave the way for developing single molecules with dual therapeutic modalities as a new strategy for GBM treatment. Additional pre-clinical studies are ongoing to evaluate the ability of ZR2002 to cross the blood brain barrier and its efficacy in an orthotopic tumor brain model. This research is funded by the Canadian Cancer Society grant #70217. Citation Format: Zeinab Sharifi, Jean-Claude Bertrand, Kevin Petrecca, Elliot Goodfellow, Bassam Abdulkarim, Siham Sabri. Anti-proliferative effects of ZR2002, a novel combi-molecule with EGFR/DNA binary targeting properties compared to Gefitinib in glioblastoma cell lines and brain tumor stem cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4235. doi:10.1158/1538-7445.AM2015-4235
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".