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MA17 - Molecular Mechanisms and Therapies (ID 143)
- Event: WCLC 2019
- Type: Mini Oral Session
- Track: Biology
- Presentations: 1
- Now Available
- Moderators:Eloisa Jantus-Lewintre, Hongbin Ji
- Coordinates: 9/09/2019, 15:45 - 17:15, Melbourne (1991)
MA17.10 - Lactate Transporter Blockade as a Strategy to Overcome VEGF Inhibitor-Resistance in LKB1-Deficient NSCLC (Now Available) (ID 2647)
15:45 - 17:15 | Author(s): Barbara Mino
STK11/LKB1 alterations are found in 20-30% of NSCLC and used to co-occur with KRAS mutations. Because LKB1 activates AMPK, many of the best known functions of LKB1 are attributed to its ability to control metabolic alterations in cells. Our laboratory have previously reported that loss of LKB1 promotes enhanced glycolysis and elevated lactate production and more recently we demonstrated that STK11/LKB1 mutations are the strongest predictors of de novo resistance to immunotherapy in NSCLC. Prior studies have revealed an association between alterations in the LKB1/AMPK pathway and worse clinical outcomes in NSCLC and in patients treated with chemotherapy and bevacizumab. Given the roles of LKB1 in the regulation of cell metabolism and resistance to immunotherapy, it is feasible that LKB1 also impacts on the response to anti-angiogenic therapies.Method
Xenograft mouse models were established by subcutaneous injection of H460 cells (LKB1-deficient) and H460 LKB1-expressing in nude mice and LKR10 (KRASG12D) LKB1 wild-type (K) or LKB1- knockout (KL) into 129Svmice. Mice were randomized to vehicle or B20-4.1.1 anti-VEGF antibody. Glycolytic activity of LKB1-intact and -deficient NSCLC cells was measured by Seahorse assay. We analyzed gene expression of SLC16A3 (MCT4) by qPCR and Western blot. Genetic disruption of MCT4 in the K and KL cell lines was done using CRISPR-Cas9 and mouse models were established by subcutaneous injection into mice.Result
Mice bearing LKB1-expressing H460 xenografts treated with anti-VEGF antibody showed a significant decrease in tumor volume (p<0.05) compared with their vehicle-treated counterparts. However, mice bearing LKB1-deficient H460 xenografts showed markedly reduced efficacy of anti-VEGF therapy compared with that in LKB1-expressing xenografts. Anti-VEGF therapy significantly reduced growth of LKR10 K tumors (p<0.001) but not in LKR10 KL tumors. Microvascular density was not increased in KL tumors following anti-VEGF treatment compared to K. Human isogenic LKB1-deficient cells showed a significantly increased rate of glycolysis and lactate secretion compared with cells expressing LKB1. Human and murine LKB1-deficient cells also had increased MCT4 expression compared to K cells. Immunofluorescence and RPPA analysis of tumor samples from the K and KL mouse models showed that KL tumors upregulated MCT4 protein expression compared with K tumors (p<0.0001). The genetic disruption of MCT4 KL tumors significantly improved tumor volume reduction to anti-VEGF therapies in vivo (p<0.001).Conclusion
LKB1 loss is associated with increased lactate secretion and resistance to VEGF inhibition in NSCLC. The targeting of the lactate transporter MCT4 enhance the sensitivity of LKB1-deficient NSCLC to anti-VEGF therapy.
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P1.04 - Immuno-oncology (ID 164)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Immuno-oncology
- Presentations: 2
- Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall
P1.04-07 - Immune Suppressive Microenvironment and Highly Clonal Concordance of TCR Repertoire in Brain Metastases from Non-Small Cell Lung Cancer (ID 2018)
09:45 - 18:00 | Author(s): Barbara Mino
The tumor immune microenvironment (TIME) of lung cancer brain metastasis is largely unexplored. We performed immune profiling and sequencing analysis of paired resected primary tumors and brain metastases of non-small cell lung carcinoma (NSCLC).Method
TIME profiling of archival formalin-fixed and paraffin embedded specimens of paired primary tumors and brain metastasis from 39 patients with surgically resected NSCLCs was performed using a 770 immune gene expression panel (NanoString Technologies, Seattle, WA) and by T cell receptor beta repertoire (TCRß) sequencing (Adaptive Biotechnologies, Seattle, WA). Immunohistochemistry was performed for validation. Targeted sequencing was performed to catalog hot spot mutations in cancer genes (ThermoFisher Scientific, Waltham, MA).Result
Somatic hot spot mutations were mostly shared between both tumor sites (28/39 patients; 71%). We identified 161 differentially expressed genes, indicating inhibition of dendritic cell maturation, Th1, and leukocyte extravasation signaling pathways, in brain metastases compared to primary tumors (p < 0.01). The proinflammatory cell adhesion molecule vascular cell adhesion protein 1 was significantly suppressed in brain metastases compared to primary tumors. Brain metastases exhibited lower T cell and elevated macrophage infiltration compared with primary tumors (p < 0.001). T cell clones were expanded in 64% of brain metastases compared with their corresponding primary tumors. Further, while TCR repertoires were largely shared between paired brain metastases and primary tumors, T cell densities were sparse in the metastases.Conclusion
We present findings that the TIME in brain metastases is immunosuppressed when compared to matched primary tumors in NSCLC patients, and that thus may help guide immunotherapeutic strategies for NSCLC brain metastases.
P1.04-79 - CD73 Expression in Lung Adenocarcinomas and Immunological and Molecular Associations (ID 2412)
09:45 - 18:00 | Author(s): Barbara Mino
Immune checkpoints inhibitors (ICI), in monotherapy or combination with chemotherapy, are the standard of care for lung adenocarcinoma (ADC) patients. Unfortunately, only a restricted number of patients will respond to ICI. Combination therapies such as CD73 inhibitors, are being studied with the goal to achieve synergic effects. CD73 is a membrane-bound protein with immunosuppressive functions. We previously reported that higher immune cell infiltration was associated mainly to CD73 basolateral (BL) expression, in this abstract, we show the correlation of CD73 expression at luminal (L) and BL membrane of ADC malignant cells (MCs), with annotated clinicopathological characteristics, immune and molecular biomarkers.Method
CD73 IHC expression (clone D7F9A) was evaluated in 106 archived ADCs from patients that underwent surgical treatment without neoadjuvant therapy between February 1999 and February 2012 at MD Anderson Cancer Center (Houston, Texas, USA). We scored % and H-score of CD73 expression at the luminal (L) and basolateral (BL) membrane, we calculated the Total (T) CD73 as the average of L and BL, and classified ADCs in three groups: ‘T High’ (TH) (upper quartile for all tumors); ‘T Low’ (TL); ‘T Neg’ (TN) (<1%). We correlated T, L and BL expression and the three groups with clinicopathological characteristics, mutational status of KRAS and EGFR, TP53, STK11 and Tumor mutation burden (TMB), and cell densities of CD3, CD8, CD68, CD45RO, FOXP3, and Granzyme B, and PD-L1 expression (clone E1L3N) in MCs.Result
T CD73 expression was found in 76%; BL in 60% and L in 57%; among ADCs with luminal membrane present (n=72), L CD73 was present in 83%. T+ and L+ expression was more frequent in never smokers (p=0.02 and p=0.003). Also higher frequency of L+ was found in older patients (>65) (p=0.01), tumors with non-solid histology patterns (p<0.001), EGFR mutation (p=0.048), non-mutated p53 (p=0.002), negative PD-L1 (p=0.03), and low TMB (<10 mut/MB) (p=0.001). Higher levels of L expression were found in KRAS mutated tumors (p=0.049). Higher BL expression positively correlated with p53 mutated tumors (p=0.038), PD-L1+ in MCs (p=<0.0001), and higher TMB (p=0.040).
Our group analyses revealed that TH and TN were associated with ADCs from patients with >30 pack-year of smoking history (p=0.04), presence of any-solid histology pattern (p=0.03), p53 mutation (p= 0.005) and higher TMB (p=0.003) compared with TL. TH also had higher frequency of PD-L1+ tumors, and a higher cell density of CD3 (p=0.0001), CD8 (p=0.001), CD68 (p=0.048), CD45RO (p=0.036), FOXP3 (p=0.053), and Granzyme B (p=0.024) compared to TL and TN. TN showed higher frequency of STK11 mutation (p=0.034).Conclusion
Based on the CD73 expression we defined subsets of lung adenocarcinomas that have distinct histological, molecular and immunological characteristics that may play a role in the response to ICI.
Our characterization could help us to understand patient’s response to ICI, and identify patients that could potentially benefit from combination therapies.