Protein Tyrosine Phosphatase Non-Receptor 11 (PTPN11/Shp2) as a Driver Oncogene and a Novel Therapeutic Target in Non-Small Cell Lung Cancer (NSCLC)

PTPN11 encodes the SHP2 protein tyrosine phosphatase that activates the mitogen-activated protein kinase (MAPK) pathway upstream of KRAS and MEK. PTPN11/Shp2 somatic mutations occur frequently in Juvenile myelomonocytic leukaemia (JMML); however, the role of mutated PTPN11 in lung cancer tumourigenesis and its utility as a therapeutic target has not been fully addressed. We applied mass-spectrometry-based genotyping to DNA extracted from the tumour and matched the normal tissue of 356 NSCLC patients (98 adenocarcinomas (LUAD) and 258 squamous cell carcinomas (LUSC)). Further, PTPN11 mutation cases were identified in additional cohorts, including TCGA, Broad, and MD Anderson datasets and the COSMIC database. PTPN11 constructs harbouring PTPN11 E76A, A72D and C459S mutations were stably expressed in IL-3 dependent BaF3 cells and NSCLC cell lines (NCI-H1703, NCI-H157, NCI-H1299). The MAPK and PI3K pathway activation was evaluated using Western blotting. PTPN11/Shp2 phosphatase activity was measured in whole-cell protein lysates using an Shp2 assay kit. The Shp2 inhibitor (SHPi) was assessed both in vitro and in vivo in a PTPN11-mutated cell line for improved responses to MAPK and PI3K targeting therapies. Somatic PTPN11 hotspot mutations occurred in 4/98 (4.1%) adenocarcinomas and 7/258 (2.7%) squamous cells of 356 NSCLC patients. Additional 26 PTPN11 hotspot mutations occurred in 23 and 3 adenocarcinomas and squamous cell carcinoma, respectively, across the additional cohorts. Mutant PTPN11 significantly increased the IL-3 independent survival of Ba/F3 cells compared to wildtype PTPN11 (p < 0.0001). Ba/F3, NCI-H1703, and NCI-H157 cells expressing mutant PTPN11 exhibited increased PTPN11/Shp2 phosphatase activity and phospho-ERK1/2 levels compared to cells expressing wildtype PTPN11. The transduction of the PTPN11 inactivating mutation C459S into NSCLC cell lines led to decreased phospho-ERK, as well as decreased phospho-AKT in the PTPN11-mutated NCI-H661 cell line. NCI-H661 cells (PTPN11-mutated, KRAS-wild type) were significantly more sensitive to growth inhibition by the PI3K inhibitor copanlisib (IC50: 13.9 ± 4.7 nM) compared to NCI-H1703 (PTPN11/KRAS-wild type) cells (IC50: >10,000 nM). The SHP2 inhibitor, in combination with the PI3K targeting therapy copanlisib, showed no significant difference in tumour development in vivo; however, this significantly prevented MAPK pathway induction in vitro (p < 0.0001). PTPN11/Shp2 demonstrated the in vitro features of a driver oncogene and could potentially sensitize NSCLC cells to PI3K inhibition and inhibit MAPK pathway activation following PI3K pathway targeting.

Targeting the PI3K and MAPK pathways to improve response to HER2-targeted therapies in HER2-positive gastric cancer

Background

Aberrant PI3K signalling is implicated in trastuzumab resistance in HER2-positive gastric cancer (GC). The role of PI3K or MEK inhibitors in sensitising HER2-positive GCs to trastuzumab or in overcoming trastuzumab resistance is unclear.

Methods

Using mass spectrometry-based genotyping we analysed 105 hotspot, non-synonymous somatic mutations in PIK3CA and ERBB-family (EGFR, ERBB2, ERBB3 and ERBB4) genes in gastric tumour samples from 69 patients. A panel of gastric cell lines (N87, OE19, ESO26, SNU16, KATOIII) were profiled for anti-proliferative response to the PI3K inhibitor copanlisib and the MEK1/2 inhibitor refametinib alone and in combination with anti-HER2 therapies.

Results

Patients with HER2-positive GC had significantly poorer overall survival compared to HER2-negative patients (15.9 months vs. 35.7 months). Mutations in PIK3CA were only identified in HER2-negative tumours, while ERBB-family mutations were identified in HER2-positive and HER2-negative tumours. Copanlisib had anti-proliferative effects in 4/5 cell lines, with IC50s ranging from 23.4 (N87) to 93.8 nM (SNU16). All HER2-positive cell lines except SNU16 were sensitive to lapatinib (IC50s 0.04 µM–1.5 µM). OE19 cells were resistant to trastuzumab. The combination of lapatinib and copanlisib was synergistic in ESO-26 and OE-19 cells (ED50: 0.83 ± 0.19 and 0.88 ± 0.13, respectively) and additive in NCI-N87 cells (ED50:1.01 ± 0.55). The combination of copanlisib and trastuzumab significantly improved growth inhibition compared to either therapy alone in NCI-N87, ESO26 and OE19 cells (p < 0.05).

Conclusions

PI3K or MEK inhibition alone or in combination with anti-HER2 therapy may represent an improved treatment strategy for some patients with HER2-positive GC, and warrants further investigation in a clinical trial setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02842-1.

Abstract 3810: Persistence of smoking signature 4 in the non-small cell lung cancer genome

Introduction Lung cancer is the most common cause of cancer-related death. Carcinogenic and endogenous processes driving somatic mutation acquisition in cancer can be extracted and defined as mutational signatures using whole genome sequencing (WGS). Tobacco smoke is the main aetiological cause of lung cancer, with mutational signature 4 representing the characteristic C&gt;A transversions produced by smoking. Whilst smoking cessation has been shown to reduce lung cancer risk in epidemiological studies, there has been little exploration into the persistence of smoking 4 in NSCLC genomes after a patient has quit smoking. We investigated the extent and persistence of signature 4 in NSCLC genomes of current, ex- and never-smokers, correlating in particular with clinical history of smoking cessation.

Methods 132 NSCLC samples were resected from 131 patients in Greater Manchester. These samples were submitted to the 100,000 Genomes Project (Genomics England). WGS was performed on tumour specimens and matched blood samples. Data generated was processed by a standard pipeline devised by Genomics England. Tumour mutational burden (TMB), mutational signatures and copy number variation (CNV) were obtained. Clinical data collected included: smoking status, date of diagnosis, TNM stage, date of relapse and date of death (where relevant). Fisher's exact tests and Kruskal-Wallis tests were used for statistical comparisons, with Kaplan-Meier plots for survival.

Results Signature 4 was associated with a smoking history in 102/119 (85.7%) NSCLCs with a detailed smoking history available. In 17/119 (14.3%) patients with a smoking history but no signature 4 NSCLC, 15/17 (88.2%) patients quit smoking a median of 22 years ago (range 0.006 - 45 years). 6/7 (85.7%) never-smoker NSCLCs were non-signature 4 NSCLCs. 60/75 (80%) ex-smokers had sufficient smoking data to assess signature 4 persistence. Signature 4 endured in the lung tissue prior to tumour diagnosis for a median of 180 months (15 years) (range 1 - 600 months). There was no association between the time of smoking cessation and the time to NSCLC diagnosis (R2=0.0009, p=0.82). Non-signature 4 NSCLCs had a more diverse signature profile (signature 4: mean 4.36, 95% CI 4.13-4.58; non-signature 4: mean 5.52, 95% CI 4.95-6.09; p=&lt;0.0001) with a lower TMB (signature 4: median 9.76/Mb, 95% CI 9.8-12.7; non-signature 4: median 2.02/Mb, 95% CI 1.3-9.3; p=&lt;0.0001). There was no difference in relapse-free survival between signature 4 and non-signature 4 patients with early stage disease (signature 4: median 456 days, HR 0.999, 95% CI 0.419-2.385; non-signature 4: median 319 days, HR 1.001, 95% CI 0.417-2.399).

Conclusion The genomic alterations introduced by smoking persist for many years after smoking cessation. NSCLCs arising from smoking carry a distinctive identity compared to those from never-smokers, with higher TMBs driven primarily by signature 4. Whilst survival analysis is limited in this cohort, the pervasive contributions from smoking suggest that lung cancer screening programmes should include all patients with a smoking history.

Citation Format: Pantelis A. Nicola, Shereen Rafee, George Burghel, Andrew Wallace, Helene Schlecht, Eleanor Baker, Katie Baker, Lynsey Priest, Mathew Carter, Sharzad Moghadam, Jane Rogan, Robert G. Bristow, William Newman, Fiona H. Blackhall, Colin Lindsay. Persistence of smoking signature 4 in the non-small cell lung cancer genome [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3810.

Identification and clinical impact of potentially actionable somatic oncogenic mutations in solid tumor samples

Background

An increasing number of anti-cancer therapeutic agents target specific mutant proteins that are expressed by many different tumor types. Successful use of these therapies is dependent on the presence or absence of somatic mutations within the patient’s tumor that can confer clinical efficacy or drug resistance.

Methods

The aim of our study was to determine the type, frequency, overlap and functional proteomic effects of potentially targetable recurrent somatic hotspot mutations in 47 cancer-related genes in multiple disease sites that could be potential therapeutic targets using currently available agents or agents in clinical development.

Results

Using MassArray technology, of the 1300 patient tumors analysed 571 (43.9%) had at least one somatic mutation. Mutations were identified in 30 different genes. KRAS (16.5%), PIK3CA (13.6%) and BRAF (3.8%) were the most frequently mutated genes. Prostate (10.8%) had the lowest number of somatic mutations identified, while no mutations were identified in sarcoma. Ocular melanoma (90.6%), endometrial (72.4%) and colorectal (66.4%) tumors had the highest number of mutations. We noted high concordance between mutations in different parts of the tumor (94%) and matched primary and metastatic samples (90%). KRAS and BRAF mutations were mutually exclusive. Mutation co-occurrence involved mainly PIK3CA and PTPN11, and PTPN11 and APC. Reverse Phase Protein Array (RPPA) analysis demonstrated that PI3K and MAPK signalling pathways were more altered in tumors with mutations compared to wild type tumors.

Conclusions

Hotspot mutational profiling is a sensitive, high-throughput approach for identifying mutations of clinical relevance to molecular based therapeutics for treatment of cancer, and could potentially be of use in identifying novel opportunities for genotype-driven clinical trials.

66 The Use of Proton Pump Inhibitors in An Older Population in A Tertiary Hospital: A Patient Safety Issue?

Background

PPIs form part of the most commonly prescribed medications in Ireland. There has been emerging concern regarding the risks associated with their chronic use. PPI use has been linked with clostridium difficile infection, pneumonia, hypomagnesaemia, nephrotoxicity, hyponatraemia as well as many other GI and non GI pathologies including dementia. Therefore there has been emerging concern regarding their chronic use. The aim of our audit was to identify the spot prevalence and appropriateness of PPI use for gastro-protection in an older population of medical inpatients in accordance with NICE 2014 PPI guidance “Management of dyspepsia in adults in primary care.”

Methods

We audited the prevalence of PPI use in medically admitted patients aged ≥65 years at our institution and the use of PPIs within this population.

Patients' admission proforma, clinical notes, and drug kardex were reviewed. We collected: age, gender, past medical history, drug list, and laboratory results. This data was used to identify the prevalence and appropriateness of PPI use.

Results

The total number of medically admitted patients aged ≥65 years was 107. 52(48.5%) were prescribed PPIs. Of the 52, only 7(13.4%) had an appropriate indication:

Five patients had concomitant prescription of low dose Aspirin ± clopidogrel and a documented history of gastritis/esophagitis/duodenitis.

One patient had a hiatus hernia and gastro-esophageal reflux disease.

One patient had chronic NSAID use due to arthritis.

Subgroup analysis showed 46/52 were prescribed high dose PPI without indication.

Conclusions

Our audit confirms this showing that almost 50% of patients aged ≥ 65y admitted to our hospital have been prescribed PPIs. Furthermore, PPI prescriptions were only appropriate in 13.4%. In line with recent guidelines, NICE PPI guidance 2014 and AGA Best Practice Guidelines, our data shows there is scope to rationalise PPI use in older people with resultant cost savings and reduction in complications.

Immune checkpoint blockade for non-small cell lung cancer: What is the role in the special populations?

In recent years, non-small cell lung cancer (NSCLC) entered in a new era of anticancer treatments with the success of checkpoint inhibitors (CPIs). These are now part of daily practice from locally advanced to metastatic NSCLC. However, the registration phase III trials are highly selective and not fully representative of the patients seen in real-world clinical practice. This is particularly obvious for older and frail patients, which represent the majority of NSCLC cases worldwide. The median age of the patients enrolled in clinical trials is 10 years younger than what is seen in clinic and patients with performance status (PS) ≥2 were excluded from registration studies. No strong conclusions can be drawn from the available trials where older and frail patients have been excluded. The majority of data on efficacy according to age are derived from underpowered subgroup analysis and there are no age-specific safety data published. Current data suggest that older patients may derive a similar benefit with no increased toxicity when compared with younger patients. However, the recent development of immunotherapychemotherapy combinations and the potential higher incidence of toxicity, raise additional concerns for these populations where adequate patient selection is paramount. CPI is not recommended for patients with PS 3-4 and should be considered with caution for those with PS 2. The evidence for patients with pre-existing autoimmune disease (AID), organ transplant or chronic viral infections (such us viral hepatitis B and C or human immunodeficiency virus) is less clear and low level. Although CPI are potentially safe in selected patients with AID with minimal activity and well-controlled chronic viral infections, patients with solid organ transplant face a significant risk of graft loss and death. Therefore, a decision to treat these groups of patients should always be discussed at a multidisciplinary level.

Impact and correlation of mutational load (ML) and specific mutations (mts) assessed by limited targeted profiling (LTP) with PD-L1 tumour expression (exp) in resected non-small cell lung carcinoma (NSCLC)

11587

Background: The advent of immunotherapy represents a paradigm shift in the treatment of NSCLC compared to conventional chemotherapy. Recent studies have shown higher mts burden assessed by exome sequencing are associated with improved objective response and clinical benefit. We performed this study to evaluate the impact of ML assessment by LTP, correlating with PD-L1 exp and clinicopathological variables in resected NSCLC. Methods: NSCLC patients(pts) who underwent curative resection between 1998 and 2006 at our institution were included. PD-L1 status was assessed using Ventana SP124 antibody on archival FFPE surgical tumour specimens cores. PD-L1 was scored 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 were assessed by Sequenom MassArray including genes in MAPK and PI3K pathways. Clinical data was obtained from hospital electronic database. Results: Ninety-one pts were included, of which 51 (56.0%) were males, with a median age of 65 years (range: 42 – 82). 51.6%, n=47 with squamous histological subtypes, 46.2%, n=42 were ex-smoker and 49.5%, n=45 had Stage I disease. 23.1%, n=21 had PD-L1 positivity. 149 mts were identified of which, 32(21.5%) with PHLPP2, 31(20.9%) with PIK3R1 and 21(14.1%) with TP53. The presence of PI3K and TP53 mts are associated with positive PD-L1 status (see table). An inverse correlation of PD-L1 positivity with ML of (1 vs 2 vs 3: 53.8% vs 30.8% vs 15.4%) was noted. Conclusions: We did not identify higher PD-L1 exp with higher ML assessed by a LTP widely used in clincial practice. However, positive PD-L1 exp was correlated with PIK3R1 and TP53 mts , warranting further investigation as potential modulators or surrogates of positve PD-L1 expression. [Table: see text]

Thymidine Phosphorylase in Cancer; Enemy or Friend?

Thymidine phosphorylase (TP) is a nucleoside metabolism enzyme that plays an important role in the pyrimidine pathway.TP catalyzes the conversion of thymidine to thymine and 2-deoxy-α-D-ribose-1-phosphate (dRib-1-P). Although this reaction is reversible, the main metabolic function of TP is catabolic. TP is identical to the angiogenic factor platelet-derived endothelial-cell growth factor (PD-ECGF). TP is overexpressed in several human cancers in response to cellular stressful conditions like hypoxia, acidosis, chemotherapy and radiotherapy. TP has been shown to promote tumor angiogenesis, invasion, metastasis, evasion of the immune-response and resistance to apoptosis. Some of the biological effects of TP are dependent on its enzymatic activity, while others are mediated through cytokines like interleukin 10 (IL-10), basic fibroblast growth factor (bFGF) and tumour necrosis factor α (TNFα). Interestingly, TP also plays a role in cancer treatment through its role in the conversion of the oral fluoropyrimidine capecitabine into its active form 5-FU. TP is a predictive marker for fluoropyrimidine response. Given its various biological functions in cancer progression, TP is a promising target in cancer treatment. Further translational research is required in this area.

A rare case of nasopharyngeal carcinoma with widespread CNS metastases

Nasopharyngeal cancer is unique among head and neck cancers. Despite definitive treatment, there is a high rate of recurrence, most commonly in the bone, lung or liver. Brain metastases and particularly, leptomeningeal carcinomatosis are extremely rare. We present a case of recurrent nasopharyngeal carcinoma with brain metastases and leptomeningeal carcinomatosis in the absence of local recurrence and systemic metastases.