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K. Gately
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P1.02 - Biology/Pathology (ID 614)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P1.02-071a - Targeting Human Single Stranded DNA Binding Protein (hSSB) 1, a Novel Prognostic Factor, in Non-Small Cell Lung Cancer (ID 9210)
09:30 - 09:30 | Author(s): K. Gately
- Abstract
Background:
Lung cancer is the leading cause of cancer death worldwide. The hallmark of all malignant disease is genomic instability leading to tissue invasion, metastasis and resistance to chemotherapy, notably cisplatin. hSSB1 is a guardian of the genome with a key role in the detection and repair of DNA double-strand breaks, replication fork arrest and oxidative stress damage. Recently we have shown that hSSB1 is directly phosphorylated by DNA-PK at serine residue 134 in response to replication stress to promote cellular survival. We hypothesized that hSSB1 may play a role in the pathogenesis of non-small cell lung cancer (NSCLC) and in the mechanism of resistance to cisplatin based chemotherapy observed for (NSCLC). Therefore we evaluated the role of hSSB1 as a prognostic factor and as a potential new target for therapy.
Method:
We analyzed the prognostic significance of hSSB1 mRNA expression from public on line databases and through assessment of protein expression in an NSCLC tissue macro-array (TMA) using immunohistochemistry. hSSB1 mRNA levels were analyzed in matched normal:tumour adenocarcinoma and squamous cell tumour samples, and in a platinum sensitive vs resistant cells. We also explored the impact of hSSB1 expression on NSCLC cell lines sensitivity to cisplatin (measured by cell proliferation) by over-expressing a Flag tagged hSSB1 or depleting hSSB1 with specific small interfering (si)RNA.
Result:
hSSB1 expression was associated with poor prognosis for lung cancer, high levels of mRNA and protein expression correlating with a worse overall survival. hSSB1 mRNA levels were prognostic in adenocarcinomas only. hSSB1 mRNA was also significantly increased in both adenocarcinoma and squamous cell carcinoma compared to matched normal tissue. Furthermore, we observed that hSSB1 was upregulated in H460 cisplatin resistant cells as compared to the parental line. Knockdown of hSSB1 in H460 cells was associated with a significant increase in sensitivity to cisplatin.
Conclusion:
Our results establish hSSB1 as a prognostic factor in non-small cell lung cancer. Moreover, targeting hSSB1 may prove an effective method of reversing platinum resistance. Evaluation of the potential role of DNA-PK inhibition in inhibiting hSSB1 activation and reversing cisplatin and radiotherapy resistance in tumours with high levels of hSSB1 expression is currently ongoing.
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P2.02 - Biology/Pathology (ID 616)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 2
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.02-048 - Survival Correlation Between TP53 Gene and PD-L1 Tumour Expression in Resected Non-Small Cell Lung Carcinoma (ID 10272)
09:30 - 09:30 | Author(s): K. Gately
- Abstract
Background:
Tumour suppressor gene TP53 mutation is common in human cancers, especially playing an important role in lung cancer tumourgenesis. Some clinical studies have shown that TP53 alterations in non-small cell lung carcinoma (NSCLC) carry a worse prognosis and may relatively more resistant to chemotherapy and radiation. We conducted this study to evaluate the impact of TP53 assessed by limited targeted profiling, correlating with PD-L1 tumour expression and clinicopathological variables in resected NSCLC.
Method:
NSCLC patients who underwent curative resection between 1998 and 2006 at our institution were included. PD-L1 status was assessed using Ventana SP142 antibody on archival FFPE surgical tumour specimens, arrayed on tissue microarrays (TMAs) with triplicate 0.6 mm cores. PD-L1 was scored as positive if membranous staining was present in >1% of tumour cells aggregated across the replicate cores to address heterogeneity. In collaboration with the Lung Cancer Genomics Ireland Study, a targeted panel of 49 genes was assessed by Sequenom MassArray including TP53 and genes in MAPK and PI3K pathways. Clinicopathological data was obtained from hospital electronic database.
Result:
Seventy-two patients were included, of which 40 (58.0%) were males, with a median age of 66.0 years (range: 51.0 – 82.6). 54.2%, n=39 with adenocarcinoma histological subtypes, 45.8%, n=33 were ex-smoker and 42.9%, n=30 had Stage IB disease. Most patients had T2 stage (71.4%, n=50), N0 nodal disease (55.2%, n=37) and grade 2 differentiation (65.7%, n=46). Presence of TP53 mutation was identified in 22 patients (30.5%). Five patients had co-presence of TP53 mutation and PD-L1 positivity. There was no correlation between PD-L1 positivity with TP53 status, KRAS, PTPN11, PHLPP2, PIK3CA, MET and PIK3R1. The median disease-free survival in TP53 mutation with PD-L1 positivity was not reached. In univariate/unadjusted analysis, co-presence of TP53 mutation and PD-L1 positivity appear to have superior disease-free survival over TP53 wild-type and PD-L1 negativity, HR 0.17 (95%CI 0.01-0.78, p=0.018). A trend was seen with overall survival but not statistically significant (TP53 mutant, PD-L1 positive vs TP53 wild-type, PD-L1 negative: NR vs 23.1 months, HR 0.34 (95% CI: 0.0.5-1.11, p=0.079). Independent PD-L1 positivity appears to be associated with better prognosis: DFS HR 0.36 (95% CI 0.11-0.90, p=0.0272) and OS HR 0.47 (95% CI 0.19-0.98, p=0.0427).
Conclusion:
In our cohort, co-presence of TP53 mutation and PD-L1 expression was not associated with poorer survival among resected NSCLC patients. Independently, PD-L1 expression was associated with better survival, a finding which warrants further investigations as potential biomarker.
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P2.02-069 - Targeting Neuropilin-1 in NSCLC (ID 10205)
09:30 - 09:30 | Author(s): K. Gately
- Abstract
Background:
Neuropilin-1 (NP1) is expressed by a wide variety of human tumour cell lines and diverse human neoplasms, and is implicated in mediating the effects of VEGF on the proliferation, survival and migration of cancer cells. It is extensively expressed in tumour vasculature, where NP1 over-expression is associated with tumour progression and poor clinical outcome. In this study, we examined the effects of targeting NP1 in NSCLC both in vitro and in vivo.
Method:
A panel of NSCLC cell lines (H460, H647, A549 and SKMES) were screened for NP1 at the mRNA and protein levels by RT-PCR and Western blotting, respectively. Cellular expression and localisation of NP1 was further examined by immunocytochemistry, while a panel of retrospective resected lung tumours and matched normal tissues were stained by immunohistochemistry. The effects of targeting NP1 on cell proliferation (BrdU ELISA), apoptosis (FACS, HCS) and downstream survival signalling pathways (Western Blot) were examined under normoxic and hypoxic (0.1% O~2~) cell growth using anti-NP1 neutralising antibodies. Cell survival was assessed in response to treatment of NSCLC cells with a range of chemotherapeutic agents in combination with NP1 neutralising antibodies. Using a human xenograft model, tumour growth studies were carried out in nude mice following subcutaneous injection of NP1 over-expressing cells relative to empty vector controls.
Result:
All lung cancer cell lines examined expressed NP1 with the exception of the H460 cell line. Immunocytochemistry analysis confirmed cellular expression and localisation of this receptor, particularly in the leading edges of migrating cells, suggesting a possible role in cell migration. In a small cohort of resected NSCLC patients, tumour expression of NP1 was high relative to their matched normal lung tissues in adenocarcinoma, squamous cell and large cell neuroendocrine carcinomas. Cell proliferation and apoptosis were significantly altered in NSCLC cells expressing NP1. While hypoxia induced the expression of NP1, treatment of cells with NP1 neutralising antibodies reduced hypoxia-mediated cell proliferation and decreased expression of PI3K and MAPK signalling pathways. In a preliminary study, treatment with NP1 neutralising antibodies sensitised NSCLC cells to the cytotoxic effects of chemotherapy. In vivo, H460 cells over-expressing NP1 significantly increased tumour growth in NOD/SCID mice relative to empty vector controls.
Conclusion:
These data suggest a role for the Neuropilin-1 receptor in promoting cell survival and tumour growth in NSCLC and may offer potential as a therapeutic biological strategy in lung cancer.
