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Lixia Diao
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OA03 - Systemic Therapies for SCLC: Novel Targets and Patients' Selection (ID 121)
- Event: WCLC 2019
- Type: Oral Session
- Track: Small Cell Lung Cancer/NET
- Presentations: 1
- Now Available
- Moderators:Christine Lee Hann, Makoto Nishio
- Coordinates: 9/08/2019, 13:30 - 15:00, Hilton Head (1978)
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OA03.06 - ASCL1, NEUROD1, and POU2F3 Drive Distinct Subtypes of Small Cell Lung Cancer with Unique Therapeutic Vulnerabilities (Now Available) (ID 1433)
13:30 - 15:00 | Author(s): Lixia Diao
- Abstract
- Presentation
Background
Background: Accounting for 15% of all lung cancer diagnoses, small cell lung cancer (SCLC) is an aggressive malignancy with dismal clinical outcomes, due in part to failure to define clinical biomarkers predictive of unique, targetable vulnerabilities. Recent data has begun to delineate molecular subsets of SCLC by uncovering inter-tumoral heterogeneity in features such as DNA damage response, EMT, and neuroendocrine (NE) status. However, it remains unclear whether the subsets defined by these features are predictive of response to cancer therapies and could be employed as patient selection criteria.
Method
Methods: Using RNAseq data from 81 resected SCLC tumor samples and 62 SCLC cell lines, we applied non-negative matrix factorization (NMF) to optimize delineation of transcriptionally defined clusters. Reverse phase protein array (RPPA) and drug response data for cell lines were analyzed post-clustering to compare features between clusters. Clustering analyses were validated in vivo using CTC-derived patient xenograft (CDX) models, while single-cell RNAseq (scRNAseq) from these same models was used to assess intratumoral heterogeneity among clusters.
Result
Results: NMF identifies four biologically distinct clusters among SCLC tumor samples and cell lines, each defined almost solely by differential expression of the transcription factors ASCL1 (SCLC-A, 36%), NEUROD1 (SCLC-N, 31%), and POU2F3 (SCLC-P, 16%), including a cluster defined by the absence of all three (SCLC-Inflamed/Mesenchymal, or SCLC-IM, 17%). SCLC-A are neuroendocrine, epithelial tumors with susceptibility to drug classes including BCL-2 inhibitors. SCLC-N are neuroendocrine, cMYC-high tumors with susceptibilities including Aurora kinase inhibitors that are neither epithelial nor mesenchymal. SCLC-P are non-neuroendocrine, epithelial tumors vulnerable to PARP inhibitors and nucleoside analogs. Lastly, SCLC-IM consists of mesenchymal, non-neuroendocrine tumors with high-expression of immune checkpoints, STING-related genes, and inflammatory markers that may represent those SCLC which are sensitive to immune checkpoint blockade. scRNAseq reveals intratumoral heterogeneity among cluster assignment within tumors that fluctuates coincident with the onset of therapeutic resistance.
Conclusion
Conclusions: SCLC tumors can be assigned to one of four molecular subtypes on the basis of differential expression of three transcription factors. These subtype assignments reflect profound distinctions in underlying biology and susceptibility to a range of candidate drug classes. While subtype assignment on a single-cell basis within a tumor is largely homogeneous, rare cells from distinct subtypes (or representing multiple subtypes), as well as shifting assignments following treatment indicate the possibility of subtype-switching, or subtype-selection, as mechanisms of therapeutic resistance.
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P2.04 - Immuno-oncology (ID 167)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Immuno-oncology
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.04-19 - Neoadjuvant Chemotherapy Is Associated with Immunogenic Cell Death and Increased T Cell Infiltration in Early-Stage NSCLC (ID 1122)
10:15 - 18:15 | Author(s): Lixia Diao
- Abstract
Background
Recent success using immune checkpoint blockade (ICB) in the metastatic setting has raised the need to understand the immune microenvironment (IME) in early-stage disease. Moreover, pre-clinical evidence suggests that cytotoxic agents can modulate this IME. A recent study conducted by our group showed that non-small cell lung cancer (NSCLC) patients who received neoadjuvant chemotherapy followed by surgery (NCT), as compared to patients who received upfront surgery (US), had higher densities of CD3+ lymphocytes and CD68+ tumor-associated macrophages (TAMs). CD3+CD4+ lymphocytes and TAMs also correlated with better clinical outcomes. In this study, we explored the relationships between NCT and the IME by harvesting tumor samples of multiple surgical NSCLC cohorts.
Method
The PROSPECT microarray database was queried in NCT (n=45) and US (n=200) patients to investigate differentially expressed genes related to immunogenic cell death (ICD), susceptibility to CD8+ T cell and NK cell cytotoxicity, priming of antigen presenting cells, immunosuppressive enzymes and intra-tumoral cytokines. Available data from the ImmunogenomiC prOfiling of NSCLC (ICON) and other surgical NSCLC cohorts was evaluated to determine: 1) differential immune profiling using FACS (NCT=17; US=39) and multiplex IHC imaging (NCT=10; US=72); 2) plasma circulating cytokines (NCT=18; US=73); 3) tumor mutational burden (TMB) (NCT=40; US=61). Participants who received NCT or US were excluded according to these criteria: 1) concurrent treatment in addition to NCT; 2) sarcomatoid and small cell histologies; 3) clinical or pathological TNM Stage 4 disease; 4) synchronous malignancies other than lung.
Result
PROSPECT NCT patients expressed increased damage-associated molecular pattern (DAMP) genes (HSPA2, HSPA4, HSPE1, and S100A2; p<0.05) and T cell-related chemotaxis and antigen presentation genes (CXCR7, CD1A; p<0.05). Concordantly, the ICON cohort FACS results showed that NCT patients display increases in: 1) infiltration of CD8+ T cells (p=0.004); 2) proliferating Ki67+CD8+ T cells (p=0.02); 3) tissue resident memory CD8+CD103+ (p=0.02) and CD4+CD103+ non-Treg cells (p=0.01). Trends from the ICON multiplex IHC also highlighted increases in CD8+ T cells (p=0.09), CD20+ cells (p=0.08), as well as PD-L1+ malignant cells (p=0.08) and PD-L1+ TAMs (p=0.08) in NCT patients, the latter finding being supported by increased circulating MCP-1 (p=0.03). TMB was similar between NCT and US groups (p=0.912).
Conclusion
Our data provides the first evidence of ICD (i.e., increased DAMP gene expression) following NCT in human early-stage NSCLC. Furthermore, our data highlights the association of NCT with a favorable IME (i.e., increased T cell infiltration), supporting the rationale of NCT and ICB combinations in localized NSCLC.
