Soluble guanylate cyclase signalling mediates etoposide resistance in progressing small cell lung cancer.

Small cell lung cancer (SCLC) has a 5-year survival rate of <7%. Rapid emergence of acquired resistance to standard platinum-etoposide chemotherapy is common and improved therapies are required for this recalcitrant tumour. We exploit six paired pre-treatment and post-chemotherapy circulating tumour cell patient-derived explant (CDX) models from donors with extensive stage SCLC to investigate changes at disease progression after chemotherapy. Soluble guanylate cyclase (sGC) is recurrently upregulated in post-chemotherapy progression CDX models, which correlates with acquired chemoresistance. Expression and activation of sGC is regulated by Notch and nitric oxide (NO) signalling with downstream activation of protein kinase G. Genetic targeting of sGC or pharmacological inhibition of NO synthase re-sensitizes a chemoresistant CDX progression model in vivo, revealing this pathway as a mediator of chemoresistance and potential vulnerability of relapsed SCLC.

TIAM1-RAC1 promote small-cell lung cancer cell survival through antagonizing Nur77-induced BCL2 conformational change.

Small-cell lung cancer (SCLC), an aggressive neuroendocrine malignancy, has limited treatment options beyond platinum-based chemotherapy, whereafter acquired resistance is rapid and common. By analyzing expression data from SCLC tumors, patient-derived models, and established cell lines, we show that the expression of TIAM1, an activator of the small GTPase RAC1, is associated with a neuroendocrine gene program. TIAM1 depletion or RAC1 inhibition reduces viability and tumorigenicity of SCLC cells by increasing apoptosis associated with conversion of BCL2 from its pro-survival to pro-apoptotic function via BH3 domain exposure. This conversion is dependent upon cytoplasmic translocation of Nur77, an orphan nuclear receptor. TIAM1 interacts with and sequesters Nur77 in SCLC cell nuclei and TIAM1 depletion or RAC1 inhibition promotes Nur77 translocation to the cytoplasm. Mutant TIAM1 with reduced Nur77 binding fails to suppress apoptosis triggered by TIAM1 depletion. In conclusion, TIAM1-RAC1 signaling promotes SCLC cell survival via Nur77 nuclear sequestration.

Enrolment of older adults with cancer in early phase clinical trials-an observational study on the experience in the north west of England.

INTRODUCTION: older patients represent the majority of cancer patients but are under-represented in trials, particularly early phase clinical trials (EPCTs). MATERIAL AND METHODS: observational retrospective study of patients referred for EPCTs (January-December 2018) at a specialist cancer centre in the UK. The primary aim was to analyse the successful enrolment into EPCTs according to age (<65/65+). The secondary aims were to identify enrolment obstacles and the outcomes of enrolled patients. Patient data were analysed at: referral; in-clinic assessment and after successful enrolment. Among patients assessed in clinic, a sample was defined by randomly matching the older cohort with the younger cohort (1:1) by tumour type. RESULTS: 555 patients were referred for EPCTs with a median age of 60 years, of whom 471 were assessed in new patient clinics (38% were 65+). From those assessed, a randomly tumour-matched sample of 318 patients (159 per age cohort) was selected. Older patients had a significantly higher comorbidity score measured by ACE-27 (P < 0.0001), lived closer to the hospital (P = 0.045) and were referred at a later point in their cancer management (P = 0.002). There was no difference in suitability for EPCTs according to age with overall 84% deemed suitable. For patients successfully enrolled into EPCTs, there was no difference between age cohorts (20.1 vs. 22.6% for younger and older, respectively; P = 0.675) and no significant differences in their safety and efficacy outcomes. DISCUSSION: older age did not affect the enrolment into EPCTs. However, the selected minority referred for EPCTs suggests a pre-selection upstream by primary oncologists.

Effect of oxaliplatin plus 5-fluorouracil or capecitabine on circulating and imaging biomarkers in patients with metastatic colorectal cancer: a prospective biomarker study.

BACKGROUND: Patients with metastatic colorectal cancer are treated with cytotoxic chemotherapy supplemented by molecularly targeted therapies. There is a critical need to define biomarkers that can optimise the use of these therapies to maximise efficacy and avoid unnecessary toxicity. However, it is important to first define the changes in potential biomarkers following cytotoxic chemotherapy alone. This study reports the impact of standard cytotoxic chemotherapy across a range of circulating and imaging biomarkers. METHODS: A single-centre, prospective, biomarker-driven study. Eligible patients included those diagnosed with colorectal cancer with liver metastases that were planned to receive first line oxaliplatin plus 5-fluorouracil or capecitabine. Patients underwent paired blood sampling and magnetic resonance imaging (MRI), and biomarkers were associated with progression-free survival (PFS) and overall survival (OS). RESULTS: Twenty patients were recruited to the study. Data showed that chemotherapy significantly reduced the number of circulating tumour cells as well as the circulating concentrations of Ang1, Ang2, VEGF-A, VEGF-C and VEGF-D from pre-treatment to cycle 2 day 2. The changes in circulating concentrations were not associated with PFS or OS. On average, the MRI perfusion/permeability parameter, Ktrans, increased in response to cytotoxic chemotherapy from pre-treatment to cycle 2 day 2 and this increase was associated with worse OS (HR 1.099, 95%CI 1.01-1.20, p = 0.025). CONCLUSIONS: In patients diagnosed with colorectal cancer with liver metastases, treatment with standard chemotherapy changes cell- and protein-based biomarkers, although these changes are not associated with survival outcomes. In contrast, the imaging biomarker, Ktrans, offers promise to direct molecularly targeted therapies such as anti-angiogenic agents.

Influence of abiraterone and enzalutamide on body composition in patients with metastatic castration resistant prostate cancer.

INTRODUCTION: Loss of skeletal muscle (SM) and gain of subcutaneous fat (SCF) are known side-effects of androgen-deprivation in treatment of prostate cancer. Scarce data is available concerning the effects of abiraterone/pred (ABI) on body composition and no published data regarding enzalutamide (ENZA). Our objective was to analyse the effects of ENZA on SM/SCF and to compare the results with ABI in patients with metastatic castration-resistant prostate-cancer (mCRPC). PATIENTS AND METHODS: 54 patients starting ABI (n = 17) or ENZA (n = 37) at a single-centre between 2012 and 2018 were retrospectively identified. SM and SCF were assessed using CT-scans at baseline and after a median of 10.8 months on treatment. A deep learning image-segmentation software was used to quantify SM and SCF. In a subgroup of patients receiving ENZA within a trial, we investigated change of SM using serial timepoints. RESULTS: Median time of treatment with ABI/ENZA was 14.6 months. A significant loss of SM compared to baseline was observed for ENZA (mean loss 5.2%, p<0.0001) and ABI (mean loss 3.0%, p = 0.02). SCF was not significantly altered. The effects of both drugs did not differ significantly. Loss of SM occurred early on during treatment with ENZA. CONCLUSION: Treatment with ENZA seems to lead to a loss of SM which is comparable to that of ABI. Further evaluation in larger patient-cohorts is warranted. In routine care, counselling of patients about side effects of ABI/ENZA should include discussions about SM loss.

Brief report on the clinical characteristics of patients whose samples generate small cell lung cancer circulating tumour cell derived explants.

INTRODUCTION: Small cell lung cancer (SCLC) has a dismal prognosis. Circulating tumour cells (CTCs) can be used to generate CTC derived explants (CDX) for the study of SCLC biology and the development of novel therapeutics. We investigated whether there are demographic or clinical predictors of the success of CDX generation, and whether CDX models are representative of the SCLC patient population. METHODS: This was a single centre, retrospective analysis of SCLC patients who had participated in the CHEMORES Study. Paired blood samples were donated for CTC enumeration and CDX generation attempt at pre-treatment baseline, disease progression and intervening timepoints. Clinical and demographic data was collected from electronic records, and analysed for differences between patients whose samples did and did not generate a CDX. RESULTS: 231 paired blood samples were taken from 147 patients. 45 CDX were generated from 34 patients. CTC number was significantly higher in blood samples which successfully generated a CDX than those which didn't, at both baseline (p=<0.0001) and progression (p = 0.0001). The group with successful blood samples had a poorer performance status (p = 0.0067), and a higher proportion of patients with chemorefractory disease (p = 0.0077). Both progression free survival (PFS) (p = 0.0132) and overall survival (p=< 0.0001) were significantly shorter for patients with successful samples. CONCLUSIONS: Patients whose samples generate CDX models may have a higher disease burden and more aggressive disease. Thus, insights gained by study of SCLC CDX may have a significant impact, particularly in the SCLC subpopulation with the greatest clinical need.

Profiling of Circulating Free DNA Using Targeted and Genome-wide Sequencing in Patients with SCLC.

INTRODUCTION: SCLC accounts for approximately 250,000 deaths worldwide each year. Acquisition of adequate tumor biopsy samples is challenging, and liquid biopsies present an alternative option for patient stratification and response monitoring. METHODS: We applied whole genome next-generation sequencing to circulating free DNA (cfDNA) from 39 patients with limited-stage (LS) SCLC and 30 patients with extensive-stage SCLC to establish genome-wide copy number aberrations and also performed targeted mutation analysis of 110 SCLC associated genes. Quantitative metrics were calculated for copy number aberrations, including percent genome amplified (PGA [the percentage of genomic regions amplified]), Z-score (a measure of standard deviation), and Moran's I (a measure of spatial autocorrelation). In addition CellSearch, an epitope-dependent enrichment platform, was used to enumerate circulating tumor cells (CTCs) from a parallel blood sample. RESULTS: Genome-wide and targeted cfDNA sequencing data identified tumor-related changes in 94% of patients with LS SCLC and 100% of patients with extensive-stage SCLC. Parallel analysis of CTCs based on at least 1 CTC/7.5 mL of blood increased tumor detection frequencies to 95% for LS SCLC. Both CTC counts and cfDNA readouts correlated with disease stage and overall survival. CONCLUSIONS: We demonstrate that a simple cfDNA genome-wide copy number approach provides an effective means of monitoring patients through treatment and show that targeted cfDNA sequencing identifies potential therapeutic targets in more than 50% of patients. We are now incorporating this approach into additional studies and trials of targeted therapies.

Analysis of circulating cell-free DNA identifies KRAS copy number gain and mutation as a novel prognostic marker in Pancreatic cancer.

Serial biopsy of pancreatic ductal adenocarcinoma (PDAC), to chart tumour evolution presents a significant challenge. We examined the utility of circulating free DNA (cfDNA) as a minimally invasive approach across a cohort of 55 treatment-naïve patients with PDAC; 31 with metastatic and 24 with locally advanced disease. Somatic mutations in cfDNA were detected using next generation sequencing in 15/24 (62.5%) and 27/31 (87%) of patients with locally advanced and metastatic disease, respectively. Copy number changes were detected in cfDNA of 10 patients of whom 7 exhibited gain of chromosome 12p harbouring KRAS as well as a canonical KRAS codon 12 mutation. In multivariable Cox Regression analysis, we show for the first time that patients with KRAS copy number gain and KRAS mutation have significantly worse outcomes, suggesting that this may be linked to PDAC progression. The simple cfDNA assay we describe will enable determination of the presence of KRAS copy number gain and KRAS mutations in larger studies and clinical trials.