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S. Heavey
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P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 3
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.04-057 - Targeting PIM Kinase in NSCLC (ID 933)
09:30 - 09:30 | Author(s): S. Heavey
- Abstract
Background:
PIM proteins belong to a family of serine/threonine kinases composed of 3 isoforms, PIM1, PIM2 and PIM3, that play a key role in cell cycle regulation, have potent anti-apoptotic activity and play a role in the homing and migration of metastatic cells. Furthermore, PIM kinases have also been shown to be activated in response to Akt pathway inhibition, indicating a role in adaptive responses to inhibition of this pathway potentially leading to treatment resistance. Thus, there is a strong rationale for combining PIM kinase inhibition with inhibition of the Akt pathway (i.e., inhibitors of EGFR, PI3K, Akt and mTOR). PIM kinase has been recognised as a therapeutic target particularly in haematological malignancies however the role of PIM kinases in solid tumours and NSCLC in particular are less well characterised. This study is the first to elucidate the expression of all 3 PIM isoforms in NSCLC cell lines and patient tumours as well as to examine the effect of Inflection Bioscience Ltd novel dual PI3K/PIM kinase (IBL-202) and triple PI3K/mTOR/PIM kinase (IBL-301) targeted therapies in-vitro and in-vivo.
Methods:
PIM 1/2/3 protein expression was quantified by western blot analysis in a panel of NSCLC cell lines and 40 matched normal/tumour tissues from NSCLC patients (20 adenocarcinoma and 20 squamous cell carcinoma). PIM kinase expression was correlated to patient clinicopathological characteristics and survival data. The effectiveness of IBL-202 and IBL-301 on proliferation and apoptosis in NSCLC cell lines were examined by BrdU and Annexin V/PI FACS analysis, respectively. A head-to-head in-vivo study of IBL-202 vs. IBL-301 in xenograft nude mice formed using H1975 cells is ongoing.
Results:
All 3 isoforms of PIM kinase are highly expressed across a panel of NSCLC cell lines. PIM kinase is expressed in ~ 90% of NSCLC tumour tissues across all stages of the disease. IBL-202 and IBL-301 induced apoptosis and decreased cell proliferation in NSCLC cell lines at micromolar concentrations in-vitro. The in-vivo study is ongoing and results will be presented.
Conclusion:
PIM kinase is a promising new therapeutic target for the treatment of NSCLC patients. Dual PI3K/PIM kinase (IBL-202) and triple PI3K/mTOR/PIM kinase (IBL-301) targeted therapies have demonstrated pro-apoptotic and anti-proliferative activity in-vitro and in-vivo and should be considered in the treatment of NSCLC patients.
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P2.04-102 - Targeting Inflammatory Mediators to Overcome Intrinsic and Acquired Cisplatin Resistance in Non-Small Cell Lung Cancer (ID 1314)
09:30 - 09:30 | Author(s): S. Heavey
- Abstract
Background:
Cisplatin based doublet-chemotherapy is commonly used in non-small cell lung cancer (NSCLC) treatment with an initial objective response rate of 40-50%. However, intrinsic and acquired chemo-resistance constitutes a major clinical obstacle. The mechanisms of resistance have yet to be fully understood. We have previously demonstrated that NF-κB levels are elevated in cisplatin resistant cells (CisR) and that the use of an NF-κB inhibitor, DHMEQ, resulted in greater CisR cell death. The goal of this project is to elucidate the mechanistic links between NF-κB regulated pathways and the development of cisplatin resistant NSCLC.
Methods:
The expression of NF-κB mediators and immune regulators were assessed in an isogenic NSCLC cell line model of cisplatin resistance using qPCR arrays (252 genes). A number of targets were identified and validated using PCR. The effect of drug combinations (Cisplatin and DHMEQ) was also determined. Comet assays (DNA damage) were also performed to determine the effect of DHMEQ alone or in combination with irradiation (6 Gy).
Results:
Various chemokines and their receptors were elevated in cisplatin resistant (CisR) cells compared with cisplatin sensitive (PT). In addition, a number of key TLRs and regulators of the innate immune pathway were altered. DHMEQ enhanced cellular sensitivity to cisplatin in both PT and CisR cell lines (p<0.05). This drug also overcame the chemo-protective effect of a number of chemokines and enhanced irradiation induced DNA damage. An animal study will commence shortly using DHMEQ alone and in combination with cisplatin.
Conclusion:
Immune-modulators such as DHMEQ may be a novel viable option in addressing inflammatory mediated acquired and intrinsic NSCLC chemo-resistance. In addition, immune regulators identified in this project may provide innovative targets for immuno-oncology therapy.
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P2.04-109 - Epithelial-To-Mesenchymal Transition (EMT) and Acquired Resistance to PI3K-mTOR Inhibition in NSCLC (ID 934)
09:30 - 09:30 | Author(s): S. Heavey
- Abstract
Background:
The PI3K-Akt-mTOR pathway regulates cell growth and proliferation and is often dysregulated in NSCLC, making it an attractive therapeutic target in this setting. GDC-0980 is a selective dual inhibitor of PI3K and mTOR, which is currently in Phase II clinical trials for solid tumours. As with all targeted therapies, acquired resistance to GDC-0980 is anticipated to be a major hurdle in the success of this drug. The aims of this project are to (i) elucidate the frequency of PIK3CA mutations in an Irish cohort of NSCLC patients and (ii) develop and characterise three cell line models of resistance to GDC-0980, each representing a different molecular subtype of NSCLC, in order to identify biomarkers of response/resistance to the drug that may dictate beneficial treatment strategies.
Methods:
DNA was extracted from 250 NSCLC patient tissue samples, and screened for 547 clinically relevant mutations in 46 genes using the Sequenom platform. H460, A549, and H1975 cells were cultured in GDC-0980 at IC50 concentrations over a period of several months, along with matched ‘parent’ cell lines. Development of resistance was assessed by monthly BrdU proliferation assays. Cell growth patterns were compared across the sensitive and resistant cell lines in real time using the xCELLigence platform. Cell lines were then interrogated for alterations in DNA (Sequenom), mRNA (SABiosciences arrays profiling expression of >150 genes), miRNA (Exiqon expression profiling of 2100 miRNAs) and protein (R&D Phospho Kinase array expression profiling of 43 kinases and 2 associated total proteins, PTMScan[®] Ubiquitin Remnant Motif (K-ε-GG) Kit from CST and Western blot analysis).
Results:
PIK3CA mutations occur in ~5% adenocarcinomas & 12% squamous cell carcinomas. H1975 cells (PIK3CA mutant and activated pAkt (Ser473/Thr308), pmTOR, pS6R) were most sensitive to GDC-0980, however they were the first to develop resistance to the drug. Results obtained from xCELLigence studies identified H1975 resistant (H1975R) cells as having the highest cell index out of all parent and resistant cell lines after 100 hours of cell growth, suggesting that these are the most aggressive cells. Initially a 33 miRNA signature was identified contrasting H1975P and H1975R. qPCR validation of miR-205 (a regulator of EMT) identified expression in H1975P cells but miR-205 was undetectable in H1975R cells. mRNA expression of Zeb1 & Zeb2 (direct targets of miR-205) were increased in H1975R cells compared to H1975P cells. 1,200 proteins were found to be differentially expressed between H1975P and H1975R cells. Increased expression of EMT proteins vimentin, desmin and filamin was detected in H1975R cells (p < 0.05, fold change >2). Vimentin overexpression in H1975R cells was confirmed by western blot analyis. Activation of EMT was identified as one potential mechanism of resistance to GDC-0980 in H1975R cells.
Conclusion:
The PI3K-mTOR pathway is frequently mutated in NSCLC, in particular squamous cell carcinoma, making it an ideal therapeutic target. Acquired resistance to GDC-0980 developed rapidly in NSCLC cell lines, (4-6 months) and correlates to the induction of EMT. Further elucidation of EMT regulation is under investigation and is crucial to the design of improved treatment protocols.
